Noisy 4.2 I6 in Envoy

GMCSLE · December 7, 2004

I'm not a mechanic and I know that several of the GM motors have a tick/slapping at idle when cold but ours sounds almost like a really quiet diesel. Every time I get out of the truck with it running I think that there MUST be something wrong with it to make that much noise. I've thought that maybe it's an exhaust leak but I imagine I'd have a SES light if that were the case.

Is the 4.2 I6 just that noisy like several other cold GM motors or should I have it looked at? Performance and driveability aren't suffering and I'm not getting any check engine light. It's just concerning to hear it make that much noise.

Ed Blown Vert · December 7, 2004

Hmm... I will have to listen to mine.

My Camaro has the dreaded piston-slap.

GM-Tech · December 7, 2004

The 4.2L is not a noisy engine. No cold piston noises that I've ever heard. I can't even guess since that motor has been so trouble free. An exhaust leak wouldn't turn on the SES light unless it was so bad it was sounding like open headers.

USA1Fan · December 8, 2004

Could it be the fuel injector rails? I've read of truck owners with 5.3's that had a very quiet ticking noise. At least one determined that it wasn't piston slap and found (thanks to a service department with a stethoscope) that it was the rails. The owners were told that it's normal for these engines. Dunno if it applies to the fuel injection system on the I6's or not though.

The 4200 in my TB did the same thing, usually only noticable when I was in a McDonald's drive through and pulled close to the wall.