Oil analysis 0-20 Wolf after 10,000 km or 6,250 miles

[Vladimir2306]

Hello everyone. I'm going to post another post. I know that many people on forums recommend changing the oil more often. I got curious, so I asked the service to take a sample of the oil during the last maintenance and send it for analysis. I'm sharing the results. I translated the image using a resource because the analysis itself is in Russian, and if there are any unclear translations, please ask and we'll try to understand them.

 

[Vladimir2306]

Let's figure it out. The fuel level is 2.2%, but as far as I know, the GM standard is up to 2.5%, and everyone who has posted an oil analysis here has a level of 1.7-2-2.5%. This is true regardless of the mileage. Therefore, there is fuel contamination in the oil, but it does not depend on the mileage, as the gasoline evaporates immediately.
The acidity-alkalinity ratio honestly corresponds to the old oil at the end of its service life. Would it reach the recommended 7,500 miles? Yes, without any problems. The fact that it is already reaching the end of its service life at 6,250 miles is logical, and there is nothing to make you rush to change the oil earlier, say, at 2,000 miles or 4,000 miles. Why? We don't change the tires when the residual life is 50%. Most likely, everyone drives until the residual life is 20%, and some people change them completely. I don't see the point in changing the oil earlier. It's normal, and it hasn't turned into water or shoe polish.

 

[blanchard7684]

Vladimir,

thanks for posting the oil analysis. Your use case is definitely interesting.

The acid number is extremely high. A print of 3.92 is just under the typical limit of 4.0 in engine service.

The danger in running the AN this high is it usually indicates the oil is a ways into the process of oxidizing. Oxidized oil does not lubricate well (shear stability, etc).

The acid content is likely a combination of the higher water content and fuel content of the oil.

What is spooky is the viscosity reading may be reflective of this phenomenon occuring. A print of 7.3 cSt is right on the spec for 0w20 synthetic. But you have to wonder if this is from oxidation increasing the viscosity.

Looking at the TBN is 2.2. Most Dexos spec synthetics have a TBN of 6.5-8. This magnitude of change indicates the additves are getting consumed trying to neutralize the contaminants in the oil.

I would move the oil change interval back about 1000 miles and sample it to see how that looks.

 

[PPK_]

Appreciate the info.. every owner has a way to go for oil changes.. some like miles. some like time it has been in the engine.. i like to do the oil change/filter after 4,000 miles.. when i see the idle oil pressure look a little low.

my opinion is that as the oil thins - in the GM V8s... the bypass of oil goes up in the cylinder after the plug fires.. this oil is then injected back into the intake coking up the intake valves... which then break the valve train which is straining to open a coked up intake valve stem...

i think a 5w30 reduces the oil blowby. i have cache can and can say it is about half. so the intakes get less coating of coke on the stems.

I have even thought about adding two or three cache cans to get more of the oil going into the intake... i am lazy... what you can do.. it put your engine in park... and watch the tach. if it is solidly at 550 rpm and no up and down any.. intakes are good. if you can see any up/down.. you need to run an intake cleaner at 2k rpm to wipe out the coke... which is keeping the intake open at bit a closing... a bummer. but necessary to keep the valve train in one piece.

take care.

 

[Vladimir2306]

Vladimir,

thanks for posting the oil analysis. Your use case is definitely interesting.

The acid number is extremely high. A print of 3.92 is just under the typical limit of 4.0 in engine service.

The danger in running the AN this high is it usually indicates the oil is a ways into the process of oxidizing the oil. Oxidized oil does not lubricate well (shear stability, etc).

The acid content is likely a combination of the higher water content and fuel content of the oil.

What is spooky is the viscosity reading may be reflective of this phenomenon occuring. A print of 7.3 cSt is right on the spec for 0w20 synthetic. But you have to wonder if this is from oxidation increasing the viscosity.

Looking at the TBN is 2.2. Most Dexos spec synthetics have a TBN of 6.5-8. This magnitude of change indicates the additves are getting consumed trying to neutralize the contaminants in the oil.

I would move the oil change interval back about 1000 miles and sample it to see how that looks.

Do you mean change the oil not at 6250 miles, but at 7250-7500 miles, and see what happens to the oil at that mileage?

 

[blanchard7684]

For comparison I would do oil analysis at a lower interval meaning 5250 miles.

I would absolutely not push the oil past what you are doing now especially with how you operate the engine.

 

[Vladimir2306]

For comparison I would do oil analysis at a lower interval meaning 5250 miles.

I would absolutely not push the oil past what you are doing now especially with how you operate the engine.

understand your idea. Change the oil at 5,000 miles +/- and analyze it. I'll think about it. But on the other hand. What will I see? That the resource is a little more than 6,250 miles? It's logical. It's just that this analysis shows that at 6,250 miles it's at the end of its resource. It's not dead, there's still a little reserve. But it's already at the end of its resource. And this, as you correctly noted, is taking into account how I operate my Yukon

 

[Joseph Garcia]

I'd like to get @swathdiver 's take on the oil analysis.

 

[Fless]

My UOAs have always listed the fuel content as well under 1%. One interval was about 4k miles, and the other was a bit over 5k miles.

 

[Vladimir2306]

My UOAs have always listed the fuel content as well under 1%. One interval was about 4k miles, and the other was a bit over 5k miles.

In what generation of the GM? T1?

 

[Fless]

In what generation of the GM? T1?

GMT-800

 

[Vladimir2306]

GMT-800

Here we are talking about the L87, this is a different engine, there is no point in comparing or drawing analogies with the GMT-800.

 

[Fless]

Here we are talking about the L87, this is a different engine, there is no point in comparing or drawing analogies with the GMT-800.

I agree. Mine wasn't a direct comparison, just an observation. Basic engine design should incorporate minimizing contamination of oil with fuel.

 

[OBSandaNNBS]

Here we are talking about the L87, this is a different engine, there is no point in comparing or drawing analogies with the GMT-800.

Yeah that's true, GM will never be able to replicate that masterpiece again!
The GMT800 was the OG for the 5.3.

Jokes aside, heavy duty usage can dramatically cut oil lifespan. IE wheeling or adventures. So maybe that's why you aren't quite to 7500 miles?

 

[Vladimir2306]

Yeah that's true, GM will never be able to replicate that masterpiece again!
The GMT800 was the OG for the 5.3.

Jokes aside, heavy duty usage can dramatically cut oil lifespan. IE wheeling or adventures. So maybe that's why you aren't quite to 7500 miles?

No, I hardly drive off-road. These cars are more for the highway than for off-roading. I didn't make it to 7,500 miles because I came back from another trip of almost 4,000 miles in two weeks, and my automatic transmission broke. I took the Yukon to the service, and they changed the oil at the same time, because otherwise I would have come back in two weeks for an oil change.

 

[iamlegion]

My last 3 oil analysis I’ve never had more than .5% fuel in my gen 5 l87 for what it’s worth. I have been extremely lucky though, my engine seems to be almost perfect.

 

[jerry455]

That is the weird thing about this forum, people who don't have a vehicle in this sub forum, 2021 and newer trucks, all reply how much better their older series trucks are. I am in this forum to see and read about 2021 and newer, I don't own or care about the older trucks. I have worked on many other of those and they were not perfect. These aren't perfect either but I like driving my 2021 Suburban more than any of the previous generation trucks. Each generation gets better, sure there are some problems but there were also problems when those were new as well.

 

[Joseph Garcia]

That is the weird thing about this forum, people who don't have a vehicle in this sub forum, 2021 and newer trucks, all reply how much better their older series trucks are. I am in this forum to see and read about 2021 and newer, I don't own or care about the older trucks. I have worked on many other of those and they were not perfect. These aren't perfect either but I like driving my 2021 Suburban more than any of the previous generation trucks. Each generation gets better, sure there are some problems but there were also problems when those were new as well.

There's nothing weird about that at all. Much fewer people own the 21-25 trucks than all of the people for the previous truck model years combined. As such, the member representation in numbers on this Forum will skew toward the older model trucks. In addition, new maintenance/breakdown threads and conversation will be more common with the older model trucks, simply because of their age and mileage, so new threads will also skew toward the older model trucks.

Opinions are simply opinions, and everybody has them. No right or wrong, just different.

 

[jerry455]

I thought there were sub forums for the different generations of trucks. I don't need someone who doesn't even own a 2021 -2025+, telling me how great their GMT 800 was or other useless comparisons. They can stay on their sub forum. I appreciate any constructive information but the "I would never spend that much money" or "my GMT 800 is better" doesn't help anyone. I appreciate they love their truck and hate the newer platforms and technology but I don't need to have that on this forum. I have learned a lot from others on this forum, the 2021 -2025+ but I never look in the other sub forums as I don't have those generations of trucks anymore.

 

[Fless]

I thought there were sub forums for the different generations of trucks. I don't need someone who doesn't even own a 2021 -2025+, telling me how great their GMT 800 was or other useless comparisons. They can stay on their sub forum. I appreciate any constructive information but the "I would never spend that much money" or "my GMT 800 is better" doesn't help anyone. I appreciate they love their truck and hate the newer platforms and technology but I don't need to have that on this forum. I have learned a lot from others on this forum, the 2021 -2025+ but I never look in the other sub forums as I don't have those generations of trucks anymore.

My approach is to just ignore the posts I don't need, and move on. I don't let it bother me. One doesn't need to accept every "invitation." YMMV