General motor ?

[Camprunner]

Do car engine bearing clearances get larger over many miles due to wear?

 

[Chris142]

Yes eventully. Depends on how well it was maintained. I recently had to roll new bearings in a jeep as the old ones were worn down to the copper.

 

[i_hate_autofraud]

Yup!!

I had a '72 dodge dart with a slant 6 engine (190,000 miles). At idle there was a terrible deep groan from the rear main bearings and a red oil light was On even tho it was full of oil!

So I drained the 10W30 oil and replaced with 20W50,(!!) the groan and light was gone and drove it for another 3 years!!!

 

[bvance554]

Yes. That is the definition of wear.

 

[tig1]

Recently I replaced the valve cover gaskets on both of my engines and found the valve clearance to be within factory spec.