main bearing knock? maybe maybe not
03-24-2008, 05:42 PM
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main bearing knock? maybe maybe not Hey guys..i dont know if i have some piston slap or maybe a man bearing taking a poop..when i first start it you can hear what sounds to be a slight knock/slap but if i drive it around for a little bit and its good and warm it tends to go away..my oil pressure is about 40 at idle and 55 to 60psi at around 2k ( driveing rpm) thats on fresh oil..I changed the oil last night and the magnetic plug had a silver/black paste on it. i never payied much attention before ..i would think that was normal..car still screams like a champ so im thinking its piston slap, Just takes for ever to go away. but as soon as you WOT her *** its gone..what do you think? can a main bearing knock just go away when it worms up? i know a rod knocking wont, so thats out the question..let me know..thanks
03-24-2008, 10:15 PM
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Most of the time it'll be a rod bearing knocking, not a main. They actually get worse under load and as the engine warms up and the oil thins. Sounds like you have piston slap, the clearance between the piston and cylinder walls lessens as the piston warms up and expands. Run it by a trusted mechanic or GM dealer and let an experienced ear give it a listen, I'm sure it'll make you sleep better if you know for certain.
03-24-2008, 10:59 PM
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iv let a few people listen to it and everyone gives me there opinion,most say pinion slap and one guy said a main bearing thats what got me a little worried..oh well guess ill find out friday when i throw the juice to here..then ill have to talk the wife into letting me spend the tax return..lol
