99 silverado engine noise

[1stStateChevy]

When in park if engine is reved there is a dinging sound drivers side in motor,,  start to drive and it goes away.  Rocker arm or valve spring possible? Any suggestions on how to trouble shoot, I was under it yesterday while running and cannot locate source.

[muddkatt]

Does it make the noise ONLY when you first start the truck and then disappear after about 1 to 2 minutes and not return as long as the engine is warmed up? What engine?

[1stStateChevy]

motor is 6.0  only goes away when you drive it, not the typical chevy tap , much worse , I have valve cover off on the side it is coming from now but do not see anything unusual yet

[Mike GMC]

While the cover is off, turn the engine with the crank bolt so you unload each valve.  Check each one for looseness.  Also might want to pull your pushrods and make sure they aren't bent.

[1stStateChevy]

While the cover was off I ran it, and did not see anything out of the ordinary but will pull back off and turn crank to check to see if one is loose , I have a feeling possible a collapsed lifter

 

[1stStateChevy]

Could not have been any further off on what I thought the issue was!!!  I took it in to reputable local guy , it was a bolt in the torque conv that had backed out that was hitting the inside of the housing --- he told me it is a common problem for the 6.0

[Mike GMC]

It seems to happen to some 5.3's as well.  Mine did it, but the noise seemed to come from the block area on the passenger side.  Sounds like a spun rod bearing.

[1stStateChevy]

It definitely is a scary sound, I was convinced it was in the motor , well at least the guy that fixed it was honest , could have taken me for a ride