Does this sound like rod knock? Please help.

[trx2stroke4life39]

Hello,

I have a knocking sound in my engine as well, it is a 2003 GMC Yukon with the 5.3 liter engine. HOWEVER, it only knocks for a short while when it is cold. What could be the problem? Could it be a valve lifter?

THANKS in advance, you guys are great!

That sounds more like piston slap.

[johanh13]

That sounds more like piston slap.

That sounds serious, how much longer will it go? It has only 150,000 miles on it...

[WARLOCK]

Very common. Dont worry.

[txarkitekt]

unbolt the converter from the flywheel,push it back and then start the truck and see if you still hear the knocking. Sounds like wrist pins but I may be wrong. If its no longer there then its something in the trans or converter.

Good advice Greg. Try that first. If that doesn't cure it--I would suspect the oil pump. How is your oil pressure? Put a mechanical gauge on it and see what you get. If its not at least 38-40 psi at idle, that is where your problem is. If your pressure is ok, then try changing weights of oil.

That sounds serious, how much longer will it go? It has only 150,000 miles on it...

No need to worry. Run it that way for another 150k miles.