Oil life %... How accurate is it?

[GranPrix]

Like the title says, how accurate is it? And just out of curiosity, what are some of your oil change intervals?

 

[Hi-psi]

Of course there's no way it can truly measure the "life" of the oil, but from things I've read it doesn't have a bit more intelligence built into it than just a mileage or hour timer.

Supposedly it measures a lot of different things to decide how slowly or quickly it subtracts a percentage point. Number of cold starts, run time after start, mileage, oil temp, average rpm range, etc, etc. So a vehicle that has a lot of starts, short mileage trips, etc will have the oil life reduce more rapidly than something that just does a lot of long trips.

 

[Derick]

Sounds like the oil gauge runs about 7500-8000 miles. That's too much for me....probably just my brainwashing and all. From what I understand timing chain vehicles are much dirtier than those with belts. I did my 2006 sequoia at 5k, and it was still very clean. I did the burb at 3k, and it was pretty dirty. Now, I dont know what oil was in it prior to my ownership, so I put in synthetic and assume that it's starting to break up sludge and will be dirty quicker than usual for the next few oil changes.

Now, that said. I have to ask, how many miles on your truck? If it's under 125k, I say go do the valvoline engine guarantee. As long as you do 3k oil changes, use valvoline synthetic, and record all your oil changes w/ receipt retention, they will guarantee that your motor will last to 300k. I think that's just the easiest decision of the year. It does require 3k oil changes though, and you're only allowed 3 variances. I've had it on nearly all my vehicles except for the 2002 envoy because it was at 200k when I bought it, and the burb, which was at 142k....so no guarantee on those.

 

[swathdiver]

Like the title says, how accurate is it? And just out of curiosity, what are some of your oil change intervals?

It's as accurate as GM wants it to be. They determine what's good enough for them. The new forumulas (can't spell alogorithyms) take more information into account. I've posted all what it calculates before somewhere on here from the shop manual.

Conventional oil is dead by 5,000 miles. The LC9 in my truck runs much better after the M1 5W30 synthetic oil is changed at 5,000 miles. I'm figuring on 4,000 mile intervals from now on.

IMO 7,500 miles is much too long for these LS engines, especially the Gen V DI motors with their wispy thin oils.

 

[kbuskill]

I run my OCIs out to between 10-15k miles BUT...

I run Mobil 1 full synthetic 15,000 mile oil and I have a dual remote mount oil filter setup running two M1-301A extended performance filters and an aftermarket oil cooler so the oil system holds 8+ quarts of oil now.

Here are some oil filter specs for reference...

M1-113 (factory size oil filter)


M1-212 (this is the biggest filter you can run in the factory location due to oil pan clearance)


M1-301A (I run two of these on my Burb)


So to run some rough numbers...

Factory filter is 28.21ci

M1-212 filter is 37.95ci

M1-301 filter is 65.55ci X 2 on my truck = 131.10ci for a total of...

4.65 times the oil filtering ability of the stock filter.

3.45 times the oil filtering ability of the biggest filter you can run in the stock location.

This is not to say that a larger filter actually filters better than a smaller filter but the potential is there and the filters would also take longer to become clogged than the smaller filter if ran to the same interval.

 

[SnowDrifter]

For an accuracy test, you'll need to do some objective measurements with your oil and your drive style. Send a UOA to blackstone or other analysis company and reference w/ the OLM

 

[homesick]

I'll add 2 basic, general points...

1-- The physical size of the filter's case isn't the important factor. The ability of the filtering mateial inside to trap particles of contaminant(s) is what matters. The smaller a piece that can be trapped (measured in 'microns') the cleaner the oil is kept.

2-- The breakdown of an oil's additives is at least as inportant, maybe more so, as the oil's cleanliness in determining how long the oil can stay effective.

joe

 

[kbuskill]

I'll add 2 basic, general points...

1-- The physical size of the filter's case isn't the important factor. The ability of the filtering mateial inside to trap particles of contaminant(s) is what matters. The smaller a piece that can be trapped (measured in 'microns') the cleaner the oil is kept.

2-- The breakdown of an oil's additives is at least as inportant, maybe more so, as the oil's cleanliness in determining how long the oil can stay effective.

joe

I understand...

As far as efficiency is concerned the M1 EP filters are 99% efficient at 30 microns. As far as filters go the M1 ranks up at the top with Purolater Pure 1, K&N, Wix (Napa gold). When compared with other filters these are considered the best according to the research I have done.

And as far as the additives are concerned I agree. That is why I use the 15K mile oil.

The other thing to mention here is that with the bigger filters and the aftermarket oil cooler I am running 2+ additional quarts of oil in the system. I say 2+ because I don't know for sure how much capacity was added since I pour my oil out of 5qt jugs it hard to get an accurate measure.

What I do know is that a quart of oil is 57.75ci and my 2 filters equal 131.10ci.

So 57.75 x 2 = 115.5

And 131.10 - 115.5 = 15.6ci

So the filters alone add almost an additional 2 quarts by themselves. I say almost because my filters capacity is 2 quarts plus that left over 15.6ci and the stock filters capacity is 28.21ci which leaves it 12.61ci shy of 2 full quarts. Now if you figure in the capacity of the oil lines to and from my filter setup and oil cooler and the capacity of the oil cooler itself it is probably somewhere in the 2.5-3 quart range over stock.

I know that two 5 quart jugs will top off the truck with a little left over in one of the jugs. I just never really paid any attention to how much was left. If I had to guess I would say maybe a little over a quart.

Anyway back to my point.

While the bigger size of the filter doesn't automatically mean that the filter has more filtering material inside what it does mean is that the filter (and cooler) adds more total capacity to the oil system which in my particular case is somewhere between 33%-50% more than the original capacity of 6qts.

So if we deduce that the factory 6qt capacity and it's associated amount of additives is good for X number of miles then by adding 33%-50% (2-3qts) more capacity and their additives then we should be able to figure that the OCI should be able to be safely extended out 33%-50% further.

If you think about the oil system as a circulatory system them by adding more oil to the system the "same" oil particles don't get circulated through as many times with the same engine run time which equals cooler, cleaner oil.

At some point I should send an oil sample out and have it analyzed to see how it fairs after 10k+ miles. I just hate to spend $30-$40 on it... lol... yes I am cheap sometimes.

Who knows... with an oil analysis perhaps it would reveal that I can extend it out even further... lol

 

[dnt1010]

Very interesting that Valvoline has that guarantee seems like a person would want to SELF guarantee a 300k mile engine and do 3000 mile intervals themselves? All I know is that this 198k mile 2009 Tahoe 6.0 AFM/DOD that I recently bought has oil sludge inside the valve cover. The previous owner swears that it always had Synthetic oil and was changed per OLM. Does anyone think that it would be sludged if it was changed every 3000 miles. I sure do not think so. Now next question is does a little light sludge actually hurt anything? To me it looks like it would be equal to plaque inside your arteries and restrict flow?

 

[GranPrix]

She currently has 76k and I’m using
Valvoline Full Syn 5w30. As I type this I just hit the 4K mark since my last change and it’s reading 41% oil life.