Took delivery of a new 2001 Z 10/01, was noisy then, noisier now but seems to go away after driven for 5 - 10 miles. I've only put 1600 miles on it so far. Dealer says GM says to try MOBIL 1 first. Does anyone know of any tech bulletins on this subject?

 

it sounds like once your motor is setting for a bit, maybe the lifters are bleeding down. causing the ticking noise from the top end until they get pumped back.

have you checked the pushrods for straightness?

its a possiblity.

steve frank