AMSOIL 20w50, 11,500 miles, 1994 GM 3.8 LTR

[Rob_Roy]

A friend of mine owns this vehicle, a 1994 Chevy Lumina Van, 3.8 LTR V6. 258,614 miles currently, the engine had rod bearings replaced years ago due to a massive coolant problem (intake gasket failed). I believe he has used the 20w50 since the bearings got wiped out, to maintain proper oil pressure. He drives this van almost every day, and thinks nothing of starting it on a below zero morning with no block heater.

11,500 miles on AMSOIL 20w50 and filters, 9-10 months. He uses AMSOIL filters, both for the full flow and the AMSOIL bypass system. Both filters were run for the full OCI, with 1 quart of make-up oil. Analysis by Schaeffer's.

copper 7
iron 23
chrom 1
alum 4
lead 4
moly 17
phos 990
zinc 1137
mag 28
calcium 3623
sodium 15
potassium 10
silicon 16
visc. 15.80
sulfur 8
oxidation 77
nitration 27
soot .1
Antifreeze,H2O, & Fuel all zero.

He is happy with the performance of the 20w50, and I see nothing in the report to indicate he should change his routine.

-Robert

 

[beast3300]

Excellent motor! Thanks for posting.

 

[MolaKule]

HAs he even tried a 5W30 or 10W30.

There is something wrong here if he has to use a 20W50 to maintain oil pressure.

 

[Gary Allan]

About the only thing to comment on is the oxidation. I don't know what it is VOA, but 77 is high.

 

[addyguy]

I'm suprised a PAO-based 20W-50 would shear that much; with a quart of top-off - It's comfortably a 40-weight now.

Nice results none the less, and proves that a really thick oil doesn't hurt anything!

 

[Mokanic]

If the coolant wiped out the rods it did the same to the mains. Maybe thats why he uses 20W50.

 

[Rob_Roy]

Yes, I should have specified that the bearing replacement was not a machine-shop operation. The work was done with the engine still in the van. The mains weren't replaced (should have been), and the excessive clearance required a heavier oil to maintain oil pressure. I probably would have just pulled/repaired or swapped the engine, but it seems to be running well for him.