I just bought a 2005 GMC Envoy XL with a Vortec 4200 I-6 Lots of valve

[Southern Eye]

rattle while cold, is this normal? This car is in a+++ condition and is a 1 owner. When I start it while its cold it seems to have a diesel like sound to it like a in tune rattle to the valves. Not a broken sound but like a valve moving sound. It does go completely away after a few mins. Any ideas on what to do? I wonder if I could take it back to the dealer and just give it back?

 

[cueball94]

Southern,
I just bought the exact same car about a month ago (60k miles w/SLT package). I have the same issue, but I haven't investigated it as of yet. I bought the car in Florida and didn't have the issue (suspect choke not engaged). I came up north with it and and the cold (choke engaged) triggered the rumble. If I get any info on it, I'll let you know.

 

[Molson02536]

rattle while cold, is this normal? This car is in a+++ condition and is a 1 owner. When I start it while its cold it seems to have a diesel like sound to it like a in tune rattle to the valves. Not a broken sound but like a valve moving sound. It does go completely away after a few mins. Any ideas on what to do? I wonder if I could take it back to the dealer and just give it back?

Here you go, read up on it. It may be the issue that needs to be addressed.

keep us posted.

http://gmcowners.com/gmc-forum/showthread.php?t=10558
http://gmcowners.com/gmc-forum/showthread.php?p=14866

 

[cueball94]

Molson,
Thanks for the reply....not sure if that's the issue. It's quiet and idles smooth in park, and only rumbles while engaged in drive. After 5 minutes of warm up, it disappears. The problem is definately related to a cold idle issue.

 

[Molson02536]

Molson,
Thanks for the reply....not sure if that's the issue. It's quiet and idles smooth in park, and only rumbles while engaged in drive. After 5 minutes of warm up, it disappears. The problem is definately related to a cold idle issue.

If it's not your fan clutch, then try this which is common on the 4200 Vortec.

The cam position actuator solenoid has several oil passages passing through the middle of it, covered by a fine mesh screen. If your oil is old, sludge can build up here or just over time carbon from the oil. If you are not sure of the oil change history, you may want to look at flushing the crankcase at the next oil change.

Dump one can of Seafoam in the crankcase just before the next oil change. Run it for 100 miles or so and then change the oil. (Don't run Seafoam in the crankcase for longer than 100 miles or so.) Also be sure that only the recommended 5W-30 is put in the crankcase. Might as well also clean the throttle body which is also an issue with the Envoys.

If you think you may need to replace it.
2002-2005 licensed GM parts catalog illustration TS00-402
PART #12615873 camshaft position actuator solenoid valve (#421)
PART #12584079 camshaft position sensor (with angle connector) (#908), includes seal
http://www.compnine.com/largeimg/060425TS00-402.gif

It's #421 that you want to make sure is clean. http://i570.photobucket.com/albums/ss144/yanggoose/IMG_0327.jpg

 

[cueball94]

After 3 days of troubleshooting, the dealer found the problem. Bad motor mounts!
They were so worn, that the top and bottom plates were chattering against each other. Noise most noticeable during the fast idle rpm during a cold weather start up. $200.00 parts, $300.00 labor, plus $$$ for diagnosis.

 

[Molson02536]

After 3 days of troubleshooting, the dealer found the problem. Bad motor mounts!
They were so worn, that the top and bottom plates were chattering against each other. Noise most noticeable during the fast idle rpm during a cold weather start up. $200.00 parts, $300.00 labor, plus $$$ for diagnosis.

Glad you found the issue that needs to be addressed and sharing it with us all. Have a safe holiday season.