Synthetic or regular oil?

[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...







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

 

[stayedge]

Mobil 1 or Royal Purple

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