PU 5W30, 5843 miles, 2008 Chevy TBSS LS2

[Fulton 1]

This is the third UOA that I've done on this 2008 Chevy Trailblazer SS since I purchased it used almost two years ago. The first UOA was using Mobil1 5W30 and the most recent two were using Pennzoil Ultra 5W30. For all of the samples I have been using K&N HP-1017 filter. Only modifications to the truck are an IEATSRT8 CAI (which uses an S&B cone filter) and PCM4Less tune, both of which have been present throughout all samples. All samples were collected from the pan at the time the oil was drained (and changed). I'm somewhat concerned about the fuel dilution issue that has shown up in this most recent analysis and will probably re-test in the next 3000 miles or so to see if anything has changed. Some notes: This vehicle is one of my daily drivers and sees the bulk of its driving duty in the Fall-Winter-Spring months. Occasionally it will sit for up to a week during the summer time without being started. Fuel mileage has been consistent since I've owned the truck. My commute to work is ~30 miles each way with all but maybe 2 miles being highway. I would say that my driving is 80% highway/20% city. Average speed on the highways around here is between 65-80mph. The engine runs great and shows no signs of running rich, etc. However, I do not yet have a wideband so I can't monitor actual A/F. I am planning on upgrading my HPTuners here in the near future to add that capability, though (I have the old standard MPVI).

 

[cchase]

Wear metals look similar to my LS2. Air filter looks like it's doing a good job. What is your oil change procedure? Was the oil cold when changed or had you just returned from a drive?

 

[Fulton 1]

Originally Posted By: cchase

Wear metals look similar to my LS2. Air filter looks like it's doing a good job. What is your oil change procedure? Was the oil cold when changed or had you just returned from a drive?

Hmm... That's a good question. I usually change the oil in my cars with the engine cold, but I'm almost positive that this last time I did change it after driving it because it was on a weekday. Can that have an impact on the fuel % in the analysis?

 

[cp3]

It should have the reverse effect though, driving and getting oil up to temp should burn off any fuel in the oil. Any more idleing this OCI? It seems odd to me that this sample has much more fuel yet also a higher flash point and 100 cSt, again reverse of what you should see.

 

[Fulton 1]

Originally Posted By: cp3

It should have the reverse effect though, driving and getting oil up to temp should burn off any fuel in the oil. Any more idleing this OCI? It seems odd to me that this sample has much more fuel yet also a higher flash point and 100 cSt, again reverse of what you should see.

Nope. No more idling, short trips, or stop and go driving than previous samples. I was scratching my head last night trying to think of anything that I've done differently during this OCI and I couldn't come up with anything. I hadn't thought about the oil being up to temp when I took the sample, though. I've been ignorant to that all these years I guess. Something I will definitely pay closer attention to in the future.

 

[Brons2]

looks similar to many GM LSx engines seen around here...

 

[Artem]

this truck is just all kinds of weird... interesting.

 

[Lead Shoes]

It is probably a fluke or error on Blackstones side... I wouldn't lose sleep over it..

 

[tig1]

Once again GM engines often show higher metal numbers, but that has nothing to do with the longivity of the engine.

 

[cchase]

Originally Posted By: cp3

It should have the reverse effect though, driving and getting oil up to temp should burn off any fuel in the oil. Any more idleing this OCI? It seems odd to me that this sample has much more fuel yet also a higher flash point and 100 cSt, again reverse of what you should see.

Not if the drive was short and past oil changes were made with a cold engine that had previously been run for a reasonable distance. A short run preceding this oil change would result in a high fuel reading. A long run at any point immediately previous to this oil change or a cold oil change after a long run would result in lower fuel numbers. I wouldn't worry about it.

 

[cp3]

Originally Posted By: cchase

Not if the drive was short and past oil changes were made with a cold engine that had previously been run for a reasonable distance. A short run preceding this oil change would result in a high fuel reading. A long run at any point immediately previous to this oil change or a cold oil change after a long run would result in lower fuel numbers. I wouldn't worry about it.

I agree but assumed it was after his ~30 mile commute which I think should have been enough to burn off the fuel. Maybe it was not.

 

[Fulton 1]

Originally Posted By: cp3

Originally Posted By: cchase

Not if the drive was short and past oil changes were made with a cold engine that had previously been run for a reasonable distance. A short run preceding this oil change would result in a high fuel reading. A long run at any point immediately previous to this oil change or a cold oil change after a long run would result in lower fuel numbers. I wouldn't worry about it.

I agree but assumed it was after his ~30 mile commute which I think should have been enough to burn off the fuel. Maybe it was not.

Well, looks like I misspoke previously. I just went back and checked my maintenance records and it turns out it was a weekend that I changed the oil. That has me thinking that I may have just run some quick errands beforehand and it wasn't a long drive. This explanation makes sense and makes me feel better now. When I sample the oil again I'll be sure to do it after a lengthy drive. Thanks to all for the insight.

 

[JAG]

I think either the flashpoint or the fuel % is wrong. Blackstone uses flashpoint to calculate fuel and 390F is relatively high, so fuel would be calculated as relatively low. I'd ask for a re-test.

 

[Fulton 1]

Well, I contacted Blackstone and it looks like there was indeed an error made with my sample. They apologized and immediately sent me an amended report that no longer shows any fuel. Feeling better now