10W-40 in a chevy 2.8?

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Oct 11, 2002
Pullman WA
I've got an 84' S10 with the 2.8 V6, the manual says to use 5W-30 or 10W-30, the engine has well over a one hundred thousand on it and I have 5 extra quarts of Chevron 10W-40 I planned on trying in it, however, the manual says not to use 10W-40. Is this just for gas mileage or what? Is it safe to run the 10W-40? Thanks
I believe that the 2.8s have a weak oil pump drive and would strip the distributor end. Had a friend who had to replace the pump and distributor on his (forgot what year)S10 with the 2.8 V6. My recomendation is to go with the thinner oils like a 5w-30. The ironic thing is that the rest of the motor needs a thicker oil as it is pretty frail.
My buddy has a rebuilt 2.8 that was stroked to 3.1L. And in the process had the high pressure oil pump put in. He runs the bulk 15w-40 his father's shop has on hand and is 'fine'.

I know all about the oiling problems the 2.8L has. This guy's shop gets more than a fair share of spun bearings and the like.

Try a quality 30W and cross the fingers!

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