GMC Sierra 2500 HD L8T 6.6 gas - First UOA, PUP 5W-30, 4,500 miles

[Shatterz]

Hi All

This is my first UOA from my 2021 GMC Sierra 2500 HD 6.6 gas L8T truck has 32,000 miles. Had the truck since new, been running PUP 5W-30 with an ACDelco PF63w/filter mag since about 6,000 miles on the clock. Unfortunately this truck uses about 1 quart every 1,500-2000 miles been doing it since new it’s a common problem with some of these L8T engines it seems. I guess this seems like a good report? Curious as to why the viscosity is so low though.

Never had one of these analysis done before tell me what you think. Black stone did mess up the UOA report and states this was a duramax when I clearly filled it out for GAS truck. I’ve contacted them to correct the report, hoping what I have here is actually correct for my truck
-Tell me your thoughts!!!
-Mike

 

[Adambomb7777]

You sure it was 5w30 that went in?

 

[Shatterz]

You sure it was 5w30 that went in?

Yes always been 5w-30 every time.

But I get your point like what is up with this viscosity it’s crazy low????? It’s making me not even want to run this oil anymore

 

[Bighorn2500]

Looks a little on the light side.

Probably just lack of attention to detail on their part when they refer it as a L5P Duramax when they filled out the analysis. Iron looks nice though for the low viscosity oil. Me personally I'd go thicker especially if you tow if this is actually the correct report for your truck.

 

[MalibuRam65]

Yes always been 5w-30 every time.

But I get your point like what is up with this viscosity it’s crazy low????? It’s making me not even want to run this oil anymore

That Viscosity is low I would try M1 or Valvoline even give Castrol a try .

 

[kschachn]

For one thing I would not believe a word of that estimated fuel dilution. Try a different lab next time that measures it properly via gas chromatography and get an accurate value.

If it's fuel dilution then brand won't matter.

 

[SubieRubyRoo]

If it's fuel dilution then brand won't matter.

This is such a basic, yet vital, fact that many refuse to acknowledge.

 

[Shatterz]

For one thing I would not believe a word of that estimated fuel dilution. Try a different lab next time that measures it properly via gas chromatography and get an accurate value.

If it's fuel dilution then brand won't matter.

So Blackstone is not a reliable source to go by?

So far I’m not happy with them that they messed up the report, I have contacted them in hope it gets corrected, otherwise it was a waste of $40

 

[fantastic]

So Blackstone is not a reliable source to go by?

So far I’m not happy with them that they messed up the report, I have contacted them in hope it gets corrected, otherwise it was a waste of $40

Blackstone labs is fantastic for their averages on the furthest right column. Fuel is important but the wear trends are even more important IMO. Your report shows very good (Low) wear in almost 5k miles.

 

[kschachn]

So Blackstone is not a reliable source to go by?

So far I’m not happy with them that they messed up the report, I have contacted them in hope it gets corrected, otherwise it was a waste of $40

No. They estimate fuel dilution from flash point which isn’t reliable.

Fuel dilution is not good for the oil and a spectrographic analysis isn’t going to show all the ways it’s undesirable.

 

[Shatterz]

I spoke with Blackstone labs and they said my values are correct, just a clerical error on saying Duramax. But I’m on the fence where I should go from here, stay with this oil cause wear indicators are excellent or goto something else cause of the low viscosity after just 4,500 miles?

 

[Nick814]

Sucks that those engines burn oil. I wouldnt be pleased. Maybe switch to PUP OW40? Or a Euro SP 0W40?

 

[MParr]

Pennzoil Ultimate and Pennzoil Platinum start out with low viscosity in the 5W30.

 

[hemioiler]

No. They estimate fuel dilution from flash point which isn’t reliable.

Fuel dilution is not good for the oil and a spectrographic analysis isn’t going to show all the ways it’s undesirable.

Has anybody contacted BS and asked them about this, just to get a response or their view on how they measure fuel dilution?

 

[hemioiler]

Those wear numbers are fantastic, almost too good to be true vs the average values on the far right, no?

Even doubling the wear to make up for the difference in mileage (4500 vs 7000), something seems off for such a young engine but I could be wrong.

 

[64bawagon]

Sucks that those engines burn oil. I wouldnt be pleased. Maybe switch to PUP OW40? Or a Euro SP 0W40?

My 2021 had 11k on it when I sold it and around 50% of that was with a 12k fifth wheel attached. I never added a drop of oil to it.

 

[kschachn]

Has anybody contacted BS and asked them about this, just to get a response or their view on how they measure fuel dilution?

It’s an imprecise method at heart. Contacting them won’t do any good. Even if they are following the procedure exactly it’s still not going to be very accurate.

 

[tblt44]

I would go with another brand.
Maybe a 20k oil, they all make them and still change at same intervals.
Then test and see.

 

[Shatterz]

My 2021 had 11k on it when I sold it and around 50% of that was with a 12k fifth wheel attached. I never added a drop of oil to it.

I have a 2022 Silverado 3500 HD dually chassis cab work with the 6.6 gas that does not burn a drop. Course it’s gotta be my personal truck with this problem . Seems that some do it and some don’t. I’m very frustrated about it. I traded my 2018 Ram 2500 6.4 gas for this truck after a horrendous amount of issues with it. I love this truck but the oil use has me shaking my head. I just hit 1,000 miles yesterday on the oil change after this report sample, half a quart low on dipstick. Per GM 1 quart within 100 gallons of fuel is acceptable. 1000 miles was approximately 3 tank full (3x36 gal tank) for 108 gallons total and I used 1/2 a quart. So long story short they’ll tell me to kick rocks about it.

 

[Shatterz]

It’s an imprecise method at heart. Contacting them won’t do any good. Even if they are following the procedure exactly it’s still not going to be very accurate.

Who should I use next time to get more accurate dilution results?