Rattling engine when cold.
Thread Starter
Drifting
Joined: May 2003
Posts: 1,755
Likes: 97
From: Sandy Utah
Rattling engine when cold.
I have a 2001 coupe with 14K miles on the odo. when I start it in the morning when it is cold, I get a click like a bled down tappet. When I blip the engine to 1500rpm, noise goes away, but rattles during decelration. The deceleration rattle sounds like a worn bearing in one of the accessories or one of the belt tension idlers. Once the engine is warm, the sound goes away at least to the casual listener. I can still hear it faintly. I have heard that it might be piston slap or a cut "O" ring btween the oil pump and the oil screen. Has anyone with an '01 had this problem and what was the outcome? 
Melting Slicks
Joined: May 2005
Posts: 2,866
Likes: 123
From: gresham oregon
Its piston slap! I called GM and complained to them. I paid x amount of dollars( a lot) for my C5 and I am very anxious about the noise. They gave a 100,000 mile motor waranty! Of course they say its no big deal.
Race Director
Joined: Feb 2003
Posts: 11,133
Likes: 1
From: ~The DARKSIDE Group~
Could be valve train nosie. Very noticeable at start up. As oil is pumped up through the mottor, and the valves get oiled, the nosie diminshes. Nosie is much more noticialbe if you have headers, the materials are thinner and transport the noise more easily.
