When I bought the car the guy told me it occasionally made a little knock so I didnt worry to much, but upon first oil change what I puled out was like molassas. I called him up he said he ran 60w oil in it. So I decided to try 10w40 and wow did that knock get louder. It is sounding like its comming from the driver side. It wont do it when cold, only warmed up, and only under heavy power usualy shifting through the first 2 gears. But once it gets into overdrive or drive it goes away unless going up a hill, anyone have any idea of what it might be? I would greatly appreciate it
1987 S10 Blazer 4x4 2.8L overdrive auto engine knock on 1990 Chevrolet S10 Blazer
by Randarak in Grants Pass, OR on November 01, 2010
ANSWER by patrick mannion , November 01, 2010
Straight 60W oil was used to hide a serious problem. The engine either ran low in oil, ran out of oil or just did not have frequent oil changes. I am surprised he even admitted he used such a "heavy" oil. get it checked out. If its a serious engine problem you need to decide to fix it or cut your losses. I would be upset with the seller as no manufacturer would ever call for 60W.