Over Revved Jimmy

[Jmacky]

My wife over revved her 99 jimmy while it was still in park. Now it makes a knocking sound, im not sure yet if it is coming from the top or the bottom. Would it be possible to spin a bearing just by over revving.

[Draenor]

Given the mileage, and maintenance on the vehicle, yes. It is possible that the oil pump was starved, due to wear or due to sludge. What is the oil pressure?

[superjim]

If it has been maintained properly, it is not likely that it spun a bearing.

It is possible, but not likely.

 

If the knock is from the top/middle of the engine and not from the bottom...

 

What more likely happened is, it floated a valve and collapsed a lifter.

Just letting it idle for a few minutes will probably solve the problem.

It will eventually get oil back to it and pomp itself back up to normal.

[Mike G]

Yep... If it has good oil pressure, it is/was probably a spun rod bearing. You will probably be able to determine what side too, if you listen for a while. Let it idle for a bit and see if it goes away, but a knock is different from a ticking lifter. I just did this on my 92 K1500 5.7L back in November, she had 189k original and well cared for miles. My favorite go-to mechanic guy (when I don't want to deal with things) called and said sure enough, my diag was correct. He also said that all-in-all, it was still pretty inside too. Freshened up mild rebuild and I was back on the raod in two weeks.

--Mike

[dorman68]

It is very possible to spin a bearing while over revving an engine.