M1 T&SUV + 0W40, 6,000 miles, GMC 2.8 s-15

[bob555]

Blackstone's numbers:

Aluminum 4
Chromium 1
Iron 25
Copper 4
Lead 6
Tin 2
Molybdenum 16
Nickel 1
Potassium 14
Boron 23
Silicon 18
Sodium 8
Calcium 2388
Magnesium 292
Phosphorus 864
Zinc 1059

Viscosity=86.2
Flashpoint=405
Fuel= Antifreeze=0
water=0
Insolubles=0.5


Image of the report is here, if too large to display: http://img183.exs.cx/my.php?loc=img183&image=c385262mz.jpg

First UOA on this car, which actually has approximately 220,000 mile on the orginal engine. Purolator air filter, Wix oil filter. Previous oil was 15W40 Delo as an extra, final, rinse following ARX. At about 4,000 miles into this interval, I topped up with a quart of M1 0w40. Probably 70% highway, but not gentle, driving.

The iron number seems a bit high, but blackstone listed an universal average of !56! for that type of engine. The viscosity of 86 makes no sense to me at all based on the lack of coolant in the oil.

 

[Al]

That potassium number is indicating a very small intermitant coolant leak possibly. Keep your eye on it. Probably drove your viscosity up a tad and also the bearing wear. But for that milage..what the hey.

 

[bob555]

Is that enough potassium to equal enough coolant to raise the viscosity out of grade?

Oh and coolant leaks are definitely a possibility, it is most of the reason I ran a UOA on it...with a 60 degree GM v-6 that has original 1988 intake gaskets, it wouldn't suprise me a bit.

I have the new 5000 mobil in it now, and will do UOA on it, and watch the coolant level...

 

[BlazerLT]

I would change your air filter and make sure all the intake air assembly clamps are tight.