Synthetic or regular oil?

[ckylesworld]

I just got a 08 ltz with 25k on it and cant decide wheather to use synthetic or regular oil. Does anyone know which would be best for a 5.3 engine?

[baron]

Synthetic. Seems to be the best way to go. I haven't used anything other than synthetic in any of my vehicles in the last 10+ years.

[demonal]

Synthetic for sure.

[bigblue]

i used synthetic mobil 1, in mine, i havent had any problems with it.

[BOSS]

Amsoil full synthetic.

Synthetic oils have a prolonged life, but also have a greater heat dissipating property which is why I use it in my tranny

B

[SabrToothSqrl]

I run synthetic in all of my toys... I run synthetic in the tahoe, and change it when the oil life Monitor hits 20-30%

[Z15]

If you want to save money on oil changes, then by all means use a good synthetic oil and change it less often. 3,000 mile oil changes are a myth, you can easily go 10,000+ miles up to 25,000 miles with synthetic oils like AMSOIL. You will want to use one the meets GM high performance oil spec GM 4718M. Most synthetics mention GM 4718M in their list of claims; that's the unique spec created by General Motors for Corvette oil. It's a high-temperature requirement that tolerates less oxidation (thickening) and volatility (boil-off). Avoid bargain synthetic oils. Not all synthetic oils are made the same, you get what you pay for.

GM factory fills all Cadillac with synthetic oil meeting GM Spec 4718M. All Corvettes since the 1990's come with synthetic oil and more and more cars are requiring it.

[Zed 71]

There MAY be a problem using sythetic oil in engines that have the cylinder deactivation feature. Supposidly the mechanism that allows this function also allows oil to drain down overnight, or several hours resulting in a lifter noise and/or startup grinding noise. I know there is a TSB for the lifter noise but it is not related to oil usage.

I have seen a few threads discussing this issue after switching to synthetic and I have also experienced this. After switching back to dino oil the issues stopped. This is just an FYI, I do not have any official documentation or extensive troubleshooting completed to find the cause of the noise.

[Z15]

There is NO truth that oil is the problem, its a defect in the lifter. I have used synthetic oil in my AFM 2008 GMC for over 25,000 miles and no issues. I have over 25 customers with similar engines and no problem.

Also, synthetic oil is a class of oil and within the class of oil just about everyone has an oil of different chemistry. In others words, no 2 brands of synthetic oil are the same.

[07warwagon]

I have been using mobil 1 synthetic but since I can get 6 qt. of Royal Purple plus a K&N oil filter for $50 i decided to upgrade to Royal Purple

[NASTY GM]

Mobil 1 or Royal Purple :driver:

[07warwagon]

Royal Purple

[Zed 71]

There is NO truth that oil is the problem, its a defect in the lifter. I have used synthetic oil in my AFM 2008 GMC for over 25,000 miles and no issues. I have over 25 customers with similar engines and no problem.

Also, synthetic oil is a class of oil and within the class of oil just about everyone has an oil of different chemistry. In others words, no 2 brands of synthetic oil are the same.

The thought is that the smaller molecular size of synthetic oil brings this issue to light in cylinder deactivation equipped engines. Yes it is a design issue, but synthetic oil allows more oil loss. All the info I have read with people noticing this issue indicate the noise/startup grinding was eliminated going back to dino. These are just observations... FYI I was using Mobil 1 synthetic. I discontinued its use in the Tahoe but I still use it in my sports car.

[Z15]

The thought is that the smaller molecular size of synthetic oil brings this issue to light in cylinder deactivation equipped engines.

That's bs. The engines that have problems never came factory filled with synthetic oil. Chances are those that are saying its synthetic oil had problems before they switched to synthetic oil, but now not wanting to admit the truth look to place the blame somewhere else than were it really belongs, on the defect in the manufacture of the parts. Kind of reminds me of back in the early 1980's. Oils and owner maintainence was being blamed for a rash of camshaft failures in my GM 5.0L engines. Years later, kicking and screaming it was found out that GM has a huge amount of camshafts made with substandard steel and they were secretly warranting them.



Actually its to the contrary, the engines the come with synthetic oils from the factory are not affected by this. Its those that are not factory filled that continue to have problems and why GM is going to a new oil spec in 2011. "Some formulators who have reviewed the Dexos specification say they can only achieve it through heavy use of API Group III or polyalphaolefin base oils, due to its low Noack volatility limits." Those are synthetic btw.


polyalphaolefin base oils The base oil AMSOIL has been using for decades. Guess who AMSOIL buys it from? Can't be true? Exon-Mobil Chemical, not the be confused by Mobil 1.

Toyota is requiring synthetic oils in all new vehicles, 0W-20 btw. Ford is starting to move in that direction. So get used to it, all the synthetic oil naysayers are going to dragged kicking and screaming into using synthetic oil or continue driving their old beaters. It was the same thing back with radial tires came out in the 70's, everything that could possibly go wrong with a car or truck was blamed on radial tires.

Btw-Corvettes, all Cadillacs require synthetic oil to maintain warranty.

[Mr. B]

I use regular oil and change it every 3,000 miles. I've run synthetics in the past, and have nothing bad to say about them. But for me, I like changing it every 3,000 miles so I decided to stay with regular oil.

Having the oil changed isn't expensive, and damn cheap insurance on keeping your engine running longer. I've never really understood people that try to stretch the miles between oil changes.

[Z15]

Changing oil sooner than required is not environmentally responsible; it’s not ‘cheap insurance.’ It wastes resources. Problem is, once people get this idea in their head, its hard to convince them of the truth. Its a big marketing ploy by the quick lube industry and the oil companies say nothing because they are profiting from it. AMSOIL on the other hand has been calling this what it is since 1972, a myth that is ripping of the consumer.

Btw-Don't ever fly in a jet airplane, all they use is synthetic and they are not changing every 3,000 miles. A buddy has a 2000 Kenworth semi with cat engine and has 1.3 millions miles using synthetic oil. He was just here yesterday on his way out west to pickup a oil test kit as its time test his oil. Once a month at about 10,000 miles. He last changed oil over 50,000 miles ago and last month the oil tested good. A cat engine like he has cost around $25,000. Says he can't afford to run non-synthetic because he looses about 1.5 mpg in fuel consumption and at approx. 150,000 miles a year, that's lot of money to him.

Here is some reading on how you are being duped by 3,000 mile oil changes
Goodwrench Busts Auto Care Myths One Myth at a Time
Effort begins by educating consumers that 3,000-mile oil changes are a thing of the past (http://www.gm.com/corporate/responsibility/safety/news/2008/ols_110608.jsp)

GM, California to Bust ‘3,000 Mile Myth’ (http://www.imakenews.com/lng/e_article001118695.cfm?x=bcNt0kV,b1cwnrQf)

Debunked: The 3000 Mile Oil Change Is a Myth (http://www.calrecycle.ca.gov/UsedOil/OilChange/)

When you are ready to make the switch over to a good synthetic like AMSOIL, pm me and I'll set you with a wholesale account.

some more reading
Over the years there has been an overabundance of engine oil myths. Here are some facts you may want to pass along to customers to help debunk the fiction behind these myths.
The Pennsylvania Crude Myth -- This myth is based on a misapplication of truth. In 1859, the first commercially successful oil well was drilled in Titusville, Pennsylvania.

A myth got started before World War II claiming that the only good oils were those made from pure Pennsylvania crude oil. At the time, only minimal refining was used to make engine oil from crude oil. Under these refining conditions, Pennsylvania crude oil made better engine oil than Texas crude or California crude. Today, with modern refining methods, almost any crude can be made into good engine oil.
Other engine oil myths are based on the notion that the new and the unfamiliar are somehow "bad."

The Detergent Oil Myth -- The next myth to appear is that modern detergent engine oils
are bad for older engines. This one got started after World War II, when the government no longer needed all of the available detergent oil for the war effort, and detergent oil hit the market as “heavy-duty” oil.

Many pre-war cars had been driven way past their normal life, their engines were full of sludge and deposits, and the piston rings were completely worn out. Massive piston deposits were the only thing standing between merely high oil consumption and horrendous oil consumption. After a thorough purge by the new detergent oil, increased oil consumption was a possible consequence.

If detergent oils had been available to the public during the war, preventing the massive deposit buildup from occurring in the first place, this myth never would have started. Amazingly, there are still a few people today, 60 years later, who believe that they need to use non-detergent oil in their older cars. Apparently, it takes many years for an oil myth to die.

The Synthetic Oil Myth -- Then there is the myth that new engine break-in will not occur with synthetic oils. This one was apparently started by an aircraft engine manufacturer who put out a bulletin that said so. The fact is that Mobil 1 synthetic oil has been the factory-fill for many thousands of engines. Clearly, they have broken in quite well, and that should put this one to rest.

The Starburst Oil Myth -- The latest myth promoted by the antique and collector car press says that new Starburst/ API SM engine oils (called Starburst for the shape of the symbol on the container) are bad for older engines because the amount of anti-wear additive in them has been reduced. The anti-wear additive being discussed is zinc dithiophosphate (ZDP).

Before debunking this myth, we need to look at the history of ZDP usage. For over 60 years, ZDP has been used as an additive in engine oils to provide wear protection and oxidation stability.

ZDP was first added to engine oil to control copper/lead bearing corrosion. Oils with a phosphorus level in the 0.03% range passed a corrosion test introduced in 1942.

In the mid-1950s, when the use of high-lift camshafts increased the potential for scuffing and wear, the phosphorus level contributed by ZDP was increased to the 0.08% range.

In addition, the industry developed a battery of oil tests (called sequences), two of which were valve-train scuffing and wear tests.

A higher level of ZDP was good for flat-tappet valve-train scuffing and wear, but it turned out that more was not better. Although break-in scuffing was reduced by using more phosphorus, longer-term wear increased when phosphorus rose above 0.14%. And, at about 0.20% phosphorus, the ZDP started attacking the grain boundaries in the iron, resulting in camshaft spalling.

By the 1970s, increased antioxidancy was needed to protect the oil in high-load engines, which otherwise could thicken to a point where the engine could no longer pump it. Because ZDP was an inexpensive and effective antioxidant, it was used to place the phosphorus level in the 0.10% range.

However, phosphorus is a poison for exhaust catalysts. So, ZDP levels have been reduced over the last 10-15 years. It's now down to a maximum of 0.08% for Starburst oils. This was supported by the introduction of modern ashless antioxidants that contain no phosphorus.

Enough history. Let's get back to the myth that Starburst oils are no good for older engines. The argument put forth is that while these oils work perfectly well in modern, gasoline engines equipped with roller camshafts, they will cause catastrophic wear in older engines equipped with flat-tappet camshafts.

The facts say otherwise.

Backward compatability was of great importance when the Starburst oil standards were developed by a group of experts from the OEMs, oil companies, and oil additive companies. In addition, multiple oil and additive companies ran no-harm tests on older engines with the new oils; and no problems were uncovered.

The new Starburst specification contains two valve-train wear tests. All Starburst oil formulations must pass these two tests.

- Sequence IVA tests for camshaft scuffing and wear using a single overhead camshaft engine with slider finger (not roller) followers.

- Sequence IIIG evaluates cam and lifter wear using a V6 engine with a flat-tappet system, similar to those used in the 1980s.
Those who hold onto the myth are ignoring the fact that the new Starburst oils contain about the same percentage of ZDP as the oils that solved the camshaft scuffing and wear issues back in the 1950s. (True, they do contain less ZDP than the oils that solved the oil thickening issues in the 1960s, but that's because they now contain high levels of ashless antioxidants not commercially available in the 1960s.)

Despite the pains taken in developing special flat-tappet camshaft wear tests that these new oils must pass and the fact that the ZDP level of these new oils is comparable to the level found necessary to protect flat-tappet camshafts in the past, there will still be those who want to believe the myth that new oils will wear out older engines.

Like other myths before it, history teaches us that it will probably take 60 or 70 years for this one to die also.
- Thanks to Bob Olree – GM Powertrain Fuels and Lubricants Group

[Zed 71]

That's bs. The engines that have problems never came factory filled with synthetic oil. Chances are those that are saying its synthetic oil had problems before they switched to synthetic oil, but now not wanting to admit the truth look to place the blame somewhere else than were it really belongs, on the defect in the manufacture of the parts. Kind of reminds me of back in the early 1980's. Oils and owner maintainence was being blamed for a rash of camshaft failures in my GM 5.0L engines. Years later, kicking and screaming it was found out that GM has a huge amount of camshafts made with substandard steel and they were secretly warranting them.



Actually its to the contrary, the engines the come with synthetic oils from the factory are not affected by this. Its those that are not factory filled that continue to have problems and why GM is going to a new oil spec in 2011. Those are synthetic btw.


Read the post. It never said the engines came with synthetic oil. Issues noted after switch to synthetic, and issues not observed after switch back to dino. Again just observations with thoughts from others...

BTW I prefer to use synthetic and use it my sports car as noted in my reply.

[Mr. B]

I gave my opinion on the subject. I went back to dino oil from synthetic and I change mine every 3,000 miles. If you don't want to, fine. Do whatever you wish. And I don't think that I am being environmentally irresponsible for what amounts to maybe one extra oil change (1.5 gallons) of oil per year.

[sumo]

bottom line is you do what you feel is right for you. I go 5k on non oil life reminders and 15% on the ones that do or every 3 months on regular oil. I dont like oil to sit in my engine over 3 months even if i havent reached the mileage because oil does break down. Once it leaves the sealed bottle, air, condensation, heat, old oil remains that dont come out with a previous oil change all get absorbed in the oil sitting in the pan. Plus every oil change i rotate tires to get the max life out of tires and prevent uneven wear. It also allows me to keep an eye on break pad life.

[Lancer]

I've heard of a couple of my buddies runing BP2380 aircraft synthetic in there engines to reduce the heat transfer. Im a jet engine mech and the BP2380 is about 15/qt and its pricey but i heard its good for uses on your truck if your pushing 450+ HP and are having any type of transverse lifter noise, on the a new truck it wont effect any sensors just dont use it with a Fram filter becuase the suction thru your engine could suck the inner filter togeather causing it to cut off your oil supply...

[Jay]

Even today's basic dino oil is very good.

I've used mostly supertech full synthetic from wal-mart in my Z71 since new (mostly b/c it's cheap) and it's got 200k miles with no problems at all. 6k mile oil changes on the dot. same with my 07 yukon, but it's only got 48k miles so far. It has the cylinder deactivation feature and i've never had any problems or noise issues running synthetic.

On the other hand, my dad's 01 F-150 5.4L has 260k miles and all he's ever used in it is regular old Havoline on 4k mile oil changes. It uses about a quart between oil changes but it doesn't smoke or anything. He bought it new off the lot back in the fall of 2000. I tried to get him to use synthetic but he didn't go for it and it's worked out great so far. Even if he used synthetic who's to say it would not use a little bit of oil or run any better? With that kind of mileage trouble-free I don't see an issue. Other than replacing the water pump and alternator in the last 50k miles it's been a great truck for him.

The oil issue is overblown, IMO. Use what you feel is right for your truck and wallet. It really won't make a difference in the end. The only way I could see synthetics being reasonably better is in very rough situations like constant racing or heavy towing 100% of the time.

[BOSS]

Well....there has been some real debate over oil here, love the information guys thanks

I started reading up on additives for your drivetrain ...that's a whole different debate also. Being in and out of working on cars and motorcycles since I was 15, it's very hard to believe I didn't know certain things. Kinda made me feel dumb...went into Walmart after I did some research to read all the labels...walked out with my head hangn a little low LOL!

B

[Jay]

That's one thing people miss about engine oils. The crude oil itself is just a basic stock and doesn't do much in itself other than act as a fluid medium with a tolerance for heat and contaminants. What actually protects and cleans your engine are the additive packages that are included at the factory when the oil is made. The off-the-shelf bottled additives (lucas, prolube, etc) are just watered down versions of those additives without a large amount of base stock. Honestly, they're a waste of money since that level of additives won't help because the base stock will break down long before the additives become worn out.

I read a paper (SAE?) a long time ago that talked about engine oils. It was around the time EPA started it's modern assault on engine emissions starting the 90s. As regulations emerged requiring reduced emissions, not only did the fuels and emissions equipment on the vehicles themselves change, so did the basic engine designs and the lubricants used in them. If i can find the paper number I'll post it up. There's probably been several updated or all new versions of that topic on the SAE website now though.

This is when you saw Ford, GM, Chrysler, etc etc release all new engine designs during that era. The new engines not only were designed for more power and fuel efficiency, but took advantage of newer manufacturing techniques that allowed much tighter tolerances especially in the area of the piston ring pack for better sealing against oil consumption and blow-by into the crankcase (reduced "secondary" or evaporative emissions). Returnless fuel systems also came about for this reason.

As a result, ALL oils for on-road use had to be upgraded using additives that not only provided better protection but also fewer emissions across the board. It was a team effort between the automotive and oil industries.

The one additive that made a huge difference is Moly. It's supposed to be the "slipperiest" substance on the planet because it's like liquid micro-sized ball bearings. High-dollar race oils have a lot of this stuff and is a main reason for them being so much more expensive than regular oils. But even the basic cheap oils on the shelf had to be upgraded and so they got increased levels of that in addition to other modern synthetic compounds.

While great for F1 or NASCAR engines, in regular everyday vehicles that spend 80% or more of their time under 1/2 throttle it's kind of a waste to use such a highly developed oil. The manufacturers design these engines to last to their ~300k mile target engine life using the lowest common denominator: cheap off-the-shelf oils (that's not saying engine life to total failure, but just to the point where wear and tear brings down the power, efficiency, and emissions performance below certain thresholds). I've personally seen a 1994 chevy suburban with the old 350 small block go 350k miles on regular oil and while it still ran ok, it was way down on power and only got 10mpg. It also only smoked during initial start up which was probably the valve seals more than worn out piston rings. Newer engines and oils are supposed to eclipse this by a substantial amount.

That's why I say just buy what you "feel" is right for your engine and wallet. Oil changes are about the cheapest ownership cost of a vehicle. Whether you want to spend $50 a year on oil changes using regular oil or $200 a year on oil changes with a high-grade synthetic is irrelevant in costs since (excluding the purchase price) taxes, insurance, typical non-oil related maintenance costs, etc etc are far more expensive over the typical 300k mile design life. You rarely see anyone driving vehicles with more than 150k miles these days anyway.

Just one man's perspective.

[Poncherello]

I'm in the camp that believes the 3,000 mile oil change is a myth. I also use what the car originally came with. I have had three Tahoes in the last 7 years and always went by the oil life monitor. When the monitor reaches 0% I change it. My 2010 has 1700 miles on it and I'll probably change around 2500 miles or so only because it's a new motor. After that it'll go 7-8K miles before changes.

I have driven well over a million miles in many different cars over the years and have never experienced an oil related engine failure or any engine failure for that matter. I routinely drive 7K mile before changes in my commuter, a Lincoln MKZ. My Lexus is currently at about 10,000 miles since a change but the lease is up in 2 weeks so I'm not going to change it now.

I changed the oil in my Corvette once a year, in the spring. But that car only went about 3,000 miles a summer and then was stored all winter. I say don't waster your money on frequent oil changes or upgrading to oil not originally in the car when new.... again, I've never had an oil related failure.

[SmallXL]

What is the oil life monitor based on? # of miles and # of starts?

My wife's MB specifically runs on Mobil 1 and I've been told the "countdown of oil life" is the same running syn or dino based oil. The GM countdown is most likely the same.

It's probably takes little into account what is really going on while driving: Suzy soccer-mom driving the kids to schools in 70 degree SoCal weather or pulling 8k load while 120+ degree Arizona with moderate to high engine temps.

With extended mileage between changes for the syn users - better have a good filter because that will give out before the oil ever does (K&N, wics, etc.)


my $0.02

[Jay]

A major practice that kills oils in regular passenger cars is short drives. While your engine coolant temp can get up to 200 degrees fairly quickly, within the first few miles, the oil temps lag behind that much longer.

If the oil is never allowed to get up to 212 degrees, it can't boil out moisture (condensation) and moisture exacerbates any contaminant problems like coagulating elements from combustion gases seeping past the cylinder during the power stroke (you can't completely eliminate this... your oil would never change color if you could!). The optimum temp for oil is 220 degrees, the point where moisture boils out and the oil is hot enough to keep the additives in suspension and moving freely. Above about 250 degrees, however, you can start to damage the base stock. By the time you get to 300 degrees it's doing to your oil what happens to vegetable oil in restaurant fryers, which is breaking it down very fast and it must be replaced much more often.

The bottom line is, the additives can't work if the fluid they float in can't support them. This is how sludge can appear if you don't change the oil often enough or if it gets overheated too much or too often. If you centrifuge used oil from a well-running and maintained engine you will see a collection of sludge in the bottom of the tube. That's the stuff that becomes sludge in an engine if the oil can't keep it consolidated in suspension... again, either from too long of change intervals or if the oil is damaged.

GM has a good article on the internet about the oil life monitor. It just uses calculated values for the different factors affecting oil... like rpm, reference to coolant temp, time of operation, how much demand (throttle) is being put on the engine, etc etc. It's based on a lot of tests GM did in-house in multiple scenarios while taking oil samples at times and comparing it to an analysis of the same oil when new. Do a google search on GM oil life monitor you'll find a few articles.

[UofMZ71]

i just drive my truck into the gulf and get my oil there. Probably isnt as good as synthetic but itll do AND im helping the fishies...




:laughing1:


no but regular oil ever 5k (probably about 5 months) is good for me..

[stayedge]

Mobil 1 or Royal Purple :driver:

i found that driving on penzoil was a better drive than on royal but royal purple lasted me a whole lot longer
and where do you go to get your oil changed for 50 dollars?
i alone paid like 100 for royal and a k&n filter
thinking of going with mobil 1 i need an oil change tomorrow
lol need a little help here =]

[Danny_Z56]

Todays dino and synthetic motor oils are much better and last longer than motor oils from years ago.Go with a good name brand oil and filter and you are good to go.

[BOSS]

After reading this thread and others, I made the switch to full synth to give it a try, went with Royal Purple in my hoe and mobile one extended full synth in the Honda.

On the tahoe - I added some non-Teflon-based Zmax oil additive. Seems they were one of the only additive companies allowed to keep the majority of their claims through the big lawsuit that swept the aftermarket additive companies years ago.

Even though I've run a can of SeaFoam in the oil every 3 changes in both vehicles, I did a quick 7min GUNK engine cleaner with a few quarts of cheap dino on both changes. Drained it, and added the full synth.

Both drive much smoother :-)

B

[Z15]

Use oil additives at your own risk as you have no idea what is in them. There is no reason to use any additives with modern oils, actually the additives may lead to possible engine failure.

Aftermarket engine oil supplements are “treatments” advertised to enhance an oil’s properties. Manufacturers claim these treatments reduce friction, noise and wear; maintain higher lubricity and break down sludge and varnish, protecting the engine components. Many products advertise materials like Teflon, molybdenum or graphite; however, most fail to mention that they contain chlorine, which can be highly corrosive when mixed with water. Chlorinated paraffins were once used as extreme pressure (EP) additives in lubricants, but the practice has been discontinued in most passenger vehicle lubricants due to the corrosive side effects. These chlorinated compounds are used due to their low cost and ability to provide EP properties, but they readily react with water and combustion by-products to form acidic materials that promote corrosion of engine components and bearings.

[timjohnson22]

Synthetic is the way to go

[BWdiver]

Mobile 1 in my 05 Z71 since new with no problems and I still change it at 4,000 miles, good oil is cheap insurance.

I use no additional snake oil additives. royal purpal in rest of drivetrain.

[Coolade07]

ive used full synth ever since i hit 9000k on my 07. changed it between 3-4k miles religiously. i dont like driving the truck down til the oil monitor reads 0 because the oil is jus too dirty by that time.

i say go full synth.

if you have friends in the auto biz...use them wisely.

ive been spending $15 on full synth oil and labor each oil change w/ free tire rotation.

[FijiRob]

I run Royal Purple and am very pleased. In fact, i went 10k on my last oil change interval and decided to send the oil to a lab to see how well it held up and how well my engine was wearing.

The lab result came back perfect! The oil had maintained its viscosity and none of the levels were out of line. My engine is in top notch condition. The lab recommended continued oil change intervals at 10k.

[Okla-by God-homa]

Before I retired I spent many years as a Quality Assurance Manager for a military "Motor Pool". Oil use and consumption were always a great concern of vehicles put to the hardest usage. During routine maintenance we tested the oil utilizing an instrument that measured the amount of carbon and impurities in the oil. This is the optimal way of determining if oil indeed does need to be changed. Most people are not going to put out $2200.00 for such an instrument. Other ways of determining when oil should be changed is by actual hours of run time via the use of a "Hobbs Meter", or by mileage.

I have run Mobil 1 since it was first made available for public use; yes the military had it first for a great number of years. I have had a Volov 244 with 286,000 miles with NO oil usage as well as an S-10 with 261,000 miles again with NO oil usage. Currently both of my vehicles (Volvo S70 and 2007 Yukon XL) use Mobil 1 only. NO I do not receive money from Mobil (wish I did) but can attest to how well it works. Unlike parafin based oil synthetics do NOT break down from wear nor do they change viscosity and the "boiling point" is almost 400 degrees greater than "normal" oils.

From my Oct 4, 2009 posting in a simular thread.

Now for what you want to know. Your type of driving plays a great part in how often you change your oil, if you are using Mobil 1 a good rule of thumb is if most of your miles are from city (stop and go) then change your oil and filter every 10,000 miles. On the other hand if your miles are mostly highway then every 15,000 miles for oil and filter. I have personally tested Mobil 1 in a lab after 15,000 miles and found that if I were to filter the oil through a 6 micron filter I could put the oil right back in the vehicle. Remember, the carbon from combustion and other impurities are suspended in the oil and this causes your wear.

Also I use only WIX filters, more filter media and constructed so the flow thru utilizes all of the filter. I urge anyone to take the time to cut filters apart after they were used with a hacksaw and you can see exactly what I mean.

I do wish there was a way to specify the type of oil in use for the DCM to be more accurate....but lets face it, everyone here can do basic math.

---------- Post added at 11:22 PM ---------- Previous post was at 11:20 PM ----------

From my post two days ago in another thread.

Yes you can change to synthetic oil even on a high milage vehicle. Key things to remember:

1) Do your first change of synthetic after 4000 miles and be prepared for lots of dirty oil to come out.
2) Pay attention for any leaks to suddenly show up. Remember lots of oils out there are parafin based (wax) that leave potential leaks plugged with wax. When synthetic is introduced it starts removing that wax buildup and leaks may appear.
3) Depending on the number of miles on your vehicle you may either want to opt for a thicker viscosity of synthetic or use a "high milage" synthetic.
4) Whatever synthetic you choose feel at ease at extending your milage between changes significantly. Please see my earlier post in this thread about personal history and lab testing.

Enjoy and don't be at all suprised if after 1 - 2 thousand miles that your vehicle seems to have more pep.

[acainindy]

I have been using Royal Purple since 2009 and I am very happy with it. I use the Royal purple filter too.

[Okla-by God-homa]

Royal Purple has a good rep....never disected one of their filters.

[stepjl]

I have been running Mobil #1 SYN since I first learned about it in 1984 while working at a Mobil service station when I was a kid. There are MANY brands on syn oil now on the market, but I am a loyal Mobil #1 user. Use syn over conv oil no matter what brand. Amsoil I've read is the best $ can buy, but cost more. I run mine till it gets dirty... 4,000 to 6,000 miles. Anytime in that time frame when "I feel like it". You can run it longer as some on here have stated, but I would not go past the GM timeframe listed in your owners manual if you are under warrenty. Also, if you are going to run longer, I would still change out the filter/add a QT if going to do this every 5,000 miles or so. Mobil has a special Mobil #1 that says on the jug it is for EXTENDED use of around 15,000 miles.

[01tahoenjn]

just hit over 100,000 milesi want to switch to synthetic but my uncle has a (1995 tahoe at 180,000 miles eith no prob on regular.) But I need this thing to last forever love it to much! What do you all think?

[DTAILS]

Royal Purple full synthetic .........

I use it in my BMW, Toyota and the Tahoe.

During the summer months the BMW will run an average of 15 - 20 degrees cooler with all vehicles experiencing easier cold starts year 'round.

When I first purchased the Tahoe I noticed a slight "ticking" sound during idle. I switched over to the RP and within a few minutes of starting the Tahoe with the fresh RP in place, the "ticking" is gone. Tahoe seems to run smoother as I have come to expect with all of the vehicles I have used the RP with.

Amazon shows 5 gallon tubs @ $115 per which ends up bringing the per quart size down to around $6. Not bad since RP typically sells for about $9 per quart on average.

K&N oil filter in place for the Tahoe with RP filter on the BMW.

By the way, it is proven amongst different independent studies that even full synthetic oils begin showing "breakdown" beginning around 7500 - 8K miles regardless of the vehicle/driving behavior.

[wyattz71]

synthetic all the way

[srec1]

The only car I ever put full synthetic in from day one did not end well. 2004 Dodge Durango hemi, 117k miles, dropped a valve. I changed the oil at 5k intvervals. Of course maybe without the synthetic it would have lasted only 80k.

[Okla-by God-homa]

Driving habits do come into play. Redlining the engine and driving the dog piss out of it like I did when I was a kid will cause early failure....thankfully I got older and wiser.

[djperryalexander]

what is better anyways 09 denali..???

[DTAILS]

what is better anyways 09 denali..???

Nothing is better than full synthetic.

[1ATony]

I use Mobil 1 and WIX filters in pretty much everything I own. Mobil 1 is good stuff.

[jeffbrown65]

I use Mobil 1 fully synthetic. I change every 6K b/c i live in a state were the dust is bad.

[crash0ride]

Mobil 1 filter + Castrol GTX

I used to be a hardcore synthetic oil freak but now I think its a waste of money IMHO. If you change regular oil at the correct intervals your fine. People like to justify that it runs smoother or gets better gas mileage or whatever is a myth. Change your oil at the recommended intervals from your manufacture and your fine.


** GM don't break their engines in on synthetic for some reason I forget **

[Okla-by God-homa]

Crash0ride....your correct....their frigging cheap......but Mercedes, BMW, Ferrari, and about a half dozen others do. As I have stated before, it's your investment, so it's yours do do whatever you want with it. But, facts are facts and VERY verifiable. Hopefully ALL the posts in this thread were read and understood.

[sumo]

has anyone tried the mobile 1 Truck and suv oil? i saw this on the shelf the other day and am thinging about trying it as im due for a oil change soon.

[Metalshape]

Hi I'm new to this site I have ordered me a 2011 Denali and the first thing im doing is putting a pure power oil filter on and changing the oil to DELO SAE 15-40. I build hand made cars and bike for a living and I have a lot of toys and all run the DELO oil.. I was turned on to this oil after meeting the owner smart smart guy.. I also run the filter and fuel filter on all my vehicles.. Call him and ask for Kelly.. Super nice guy tell him Dennis from Todd's Cycle told you.. I have an account with him and could do a group purchase if there are any interest..

[felixgun]

Wow... 6 pages of heated oil debate.. awesome.. i'm due for an oil change and i've decided to switch to synthetic and get a K&N oil filter. The question is.... Royal Purple or Mobil 1 Full synthetic? I'm sure it's all opinions but I want to know which of you synthetic oil people use, and why you chose that one. Thanks guys and great debate.. to each his own!

[DTAILS]

Wow... 6 pages of heated oil debate.. awesome.. i'm due for an oil change and i've decided to switch to synthetic and get a K&N oil filter. The question is.... Royal Purple or Mobil 1 Full synthetic? I'm sure it's all opinions but I want to know which of you synthetic oil people use, and why you chose that one. Thanks guys and great debate.. to each his own!

Royal Purple .........

I currently use it in my 2008 BMW 335i (highly modified):
The car cold starts easier and on average will operate @ 15 - 20 degrees cooler during the summer months. This IS Texas so it makes a definite difference. I use the RP oil filter on this one.

Also, using it in my 1998 Toyota 4Runner (237,000 miles & counting):
Recently took this truck on a month long road trip from south Texas to Calgary, Canada. This oil change was fresh when we started out ....... the 4Runner NEVER missed a beat as there was never a need to add any oil. This trip was about 6400 miles from start to finish. Easier cold starts and noticeably smoother idle. Using RP oil filter.

Currently using it in the 2007 Tahoe (95,000 miles):
Easier cold starts, idle is unchanged & still very smooth, operating temps seem to be unchanged. Using K&N oil filter.
I am also using the Royal Purple ATF trans fluid with a factory replacement AC Delco trans filter. MUCH improved shifting where I hadn't expected there to be any difference.

[sumo]

Wow... 6 pages of heated oil debate.. awesome.. i'm due for an oil change and i've decided to switch to synthetic and get a K&N oil filter. The question is.... Royal Purple or Mobil 1 Full synthetic? I'm sure it's all opinions but I want to know which of you synthetic oil people use, and why you chose that one. Thanks guys and great debate.. to each his own!

either way, you cant go wrong. What ever is on sale that day i guess, lol

[Okla-by God-homa]

Already stated what I use and why......and if you want tempreture changes come to OKLAHOMA..... -25 windchill to +105.

[felixgun]

Ended up going with Mobil 1 synthetic. + an air freshener and tax, it cost $70.50 -- guy told me I could change it up about every 9k-10k miles

[shundal]

Ended up going with Mobil 1 synthetic. + an air freshener and tax, it cost $70.50 -- guy told me I could change it up about every 9k-10k miles

I just had mine changed with the same mobil 1 sythetic and they wrote the next change is in 4,000 miles. I was thinking it was atleast double that mileage from what i have read, so good to know i don't need to be changing it out anytime soon.

[felixgun]

Yea.. I don't actually plan on letting it get to 9-10k miles before changing, and will be keeping an eye on the oil % through the gauge/cluster read out. Once the % gets to the single digits (at 100% oil life right now) then i'm going to change it out. Will post results in how long this will actually last in my car.

[sumo]

im using mobil 1 now and im at 14%. Ive gone over 5k, so im guessing that about 6k ill be due for a change

[shundal]

i usually just go off the computer oil percentage as well. but i know 4,000 was definitely to quick for a change

[k9lovr]

Upon my first change over from regular to synthetic (Mobile 1), my oil life indicator ran down pretty quick...It suggested I do the change around 4k, which I did and the oil was pretty dark, however the second one was still at 30 something % when I changed it at 5.5k miles. So your first run may be a little quicker due to some of the crap getting out of the system. Just a thought....

[felixgun]

@nick- good to know it'll run longer after the initial switch over. Thanks!

[Okla-by God-homa]

I completely stopped paying attention to the DIC. It's only going on run time and speeds and not on the conditions the engine has run under. As smart as computers are today and the sensors that are available wouldn't it be nice if "Government Motors" wised up and gave us a true oil monitor. High quality test equipment for oil cost is in the $2200.00 range and that is for a stand alone unit. I'll stick with what has served me for 15 years now......10K between changes of Mobil 1.

[k9lovr]

I dunno enough about the GM's but I was reading on Bob's the oil guy website that most OLI systems use an algorithm to calculate the oil life, and tests of oil using the OLI as a guide shows its pretty accurate in terms of how dirty the oil is, and how much wear it has had. Does anyone know anything with regard to this?

[Ryan Willson]

I completely stopped paying attention to the DIC. It's only going on run time and speeds and not on the conditions the engine has run under. As smart as computers are today and the sensors that are available wouldn't it be nice if "Government Motors" wised up and gave us a true oil monitor. High quality test equipment for oil cost is in the $2200.00 range and that is for a stand alone unit. I'll stick with what has served me for 15 years now......10K between changes of Mobil 1.


+1

[GMC Yukon]

i used synthetic mobil 1 Truck and SUV 5w30 in my 97 Yukon sence I bought it with 72,000 miles on her..... I have 225,000. on her now and I Plow and tow a 25 ft Sea Ray...... GO Synthetic ... Plus you get about 6000 miles befor changing it.... They say you can get more...:Handshake:

[Reaper]

I currently own a 99 Yukon and have switched to Mobil1 full .
Just wanted to mention that I had a 94 Astro and used regular Quaker state in it . When I let it go it had 397,000 on it and it started and ran like new.
Didn't use or burn any oil either. Not a sound from anywhere in the engine.
I used 10w30 instead of the recommended 5w30 and added a bottle of STP at each change. (Every 6 months).

I guess time will tell if the fully synthetic is better or not.

[ChrisAU]

Upon my first change over from regular to synthetic (Mobile 1), my oil life indicator ran down pretty quick...It suggested I do the change around 4k, which I did and the oil was pretty dark, however the second one was still at 30 something % when I changed it at 5.5k miles. So your first run may be a little quicker due to some of the crap getting out of the system. Just a thought....

That is very interesting indeed and to me shows that the detergent quality of the synthetic is much better.

[Z15]

The oil life monitor (OLM) does not monitor the oil, it monitors the operation conditions of the vehicle and counts down to zero based on the assigned values in the computer program. The OLM has no idea if petrolatum or synthetic oil is in the engine so that has no bearing on when the OLM will signal time for a change.

Note-Engines that come factory filled with synthetic oil have the counter in the OLM set to a higher number than those with petroleum oil.

[07 Tahoe]

I have always used Synthetic and oil looks clean when changed every time. I usually run it till my oil life % is around 10%, roughly 7-8500 miles for me.

[ezdaar]

I have always used Synthetic and oil looks clean when changed every time. I usually run it till my oil life % is around 10%, roughly 7-8500 miles for me.

damn! Wish mine would go that long. My oil indicator goes to 20% in like a month with less than 1k miles!

But I also beat on my denali pretty hard. It see's 6k+ many many times a day.

[08OLP]

had a 94 grand am 340k drove it on the scrap truck. got 01 impala 280k
use pennzoil 10w30 fram oil filter every 5k to 7k
08 tahoe with 110k 5w30

thought about Synthetic but i think that thicker oil would give me more oil psi
what do u guys think?

[07 Tahoe]

Sorry to hear that because I know a full syn oil change is not cheap.

[felixgun]

had a 94 grand am 340k drove it on the scrap truck. got 01 impala 280k
use pennzoil 10w30 fram oil filter every 5k to 7k
08 tahoe with 110k 5w30

thought about Synthetic but i think that thicker oil would give me more oil psi
what do u guys think?

Definitely time to go full Synthetic. I used Mobil 1 synthetic oil in my 08 tahoe and it lasted foreverrrrr. I'd run it to about 10-15% too before I would change it. Cost twice as much but lasts twice as long!

[Kman]

There seems to be a ton of bad information in here regarding oil. You guys should head over to Bob Is The Oil Guy (BITOG) forums and read up.

www.BobIsTheOilGuy.com


One of the biggest myths in this thread is oil is bad if it is dark in color, or good if it is still clear. If the oil is dark in color is can still be excellent, doing its job keeping the internals clean, with a medium to high TNB content. The only way to see how an oil is doing is having an oil analysis done by a lab.

---------- Post added at 02:40 AM ---------- Previous post was at 02:26 AM ----------

Wow... 6 pages of heated oil debate.. awesome.. i'm due for an oil change and i've decided to switch to synthetic and get a K&N oil filter. The question is.... Royal Purple or Mobil 1 Full synthetic? I'm sure it's all opinions but I want to know which of you synthetic oil people use, and why you chose that one. Thanks guys and great debate.. to each his own!

Royal Purple doesn't have their oil certified by different agencies and car manufactures like Mobil1 (M1) does and other big oil brand oil manufactures like Pennzoil, etc. This speaks volumes in the oil community world (go check out Bob Is The Oil Guy).

In the United States, synthetic oils are classified as synthetic if they use III base stocks or higher. In Europe, for a synthetic oil to be considered synthetic it has to be a IV base stock.

With that said, I run M1 0w-40 in my 2001 Tahoe. It's the only M1 oil that uses IV base stocks in it's oil (true synthetic). All the other Mobil1 synthetic oils in the United States use III base stocks. M1's 0w-40 also carries the most oil certifications and is backed by more car manufactures than any other oil on the planet. It is also the most tested oil in the world when it comes to meeting these special certifications.

Take it for what it is, but certifications, testing, and manufacture support speaks way more volume to me than seeing a nice marketing campaign like Royal Purple uses.

I know M1 0w-40 is expensive and hard to find, that's why I buy it when it is on sale. I picked up 36 quarts when it was on sale at Kragen a few months back for $4.99 a quart. Over a $1 cheaper per quart than Wal-Mart at the time.

Keep in mind, M1 5w-30 is the factory fill for most, if not all GM vehicles coming off the line. With that being said, you can be assured all of GM's motor testing, hours of R&D, etc. was done with M1 5w-30. Since this is the case, a lot of people, including myself, see no point in running a different oil since the new GM vehicles are rolling off the line with this exact oil.


And a lot of people think oil filters are all built the same. That is not the case at all. The general consensus on BITOG is K&N, PureONE, Mobil1, Napa Gold, WIX, and Fram Extended Guard are the best. The worst oil filters would be any Fram that is not the Extended Guard model (Extended Guard is the only one with metal end caps inside the filter).

[nj462]

Kman,.good.info, thanks

[Tony]

Back in the 1990's and the early 2000's, totoyas were always known for having the most trouble free engines, and they never came with synthetic oil.. I'm not sure what you can take away from that. From what I've always read over the years, sythentic oil just flows better in extremely cold tempatures and thats about it.. They say conventional oils are more than you need today.. I use sythentic in my denali, only because thats what the previous owner used to use. In my other cars i have always used regular oil and never have had a problem.

[BLU AV8TR]

what viscosity should I use for a '09 tahoe with 45K? Is it Mobil1 5W-30 Full synthetic??? I've been using 5W-30 regular....

[Kman]

what viscosity should I use for a '09 tahoe with 45K? Is it Mobil1 5W-30 Full synthetic??? I've been using 5W-30 regular....

Mobil1 is synthetic. Mobil is regular. Run whatever it says in the manual.