clunk sound on idle when cold

spearenvoy · March 14, 2005

I have a 2004 Envoy 4.2 I6 that has a (clunk-clunk -clunk) sound coming from the engine when it is in idle. It only does it when cold and it goes away after about ten minutes of driving. the Sound varies with speed and after 1500 rpm it seems to dissapear but when it returns to idle the noise returns. Any ideas.....

Also, is there any way to get rid of the AC vent odor when it is not in "recirculate"?

GM-Tech · March 14, 2005

Could this be more of a rather loud click, like a solenoid, rather than a knock?

Not sure what kind of odor you mean. If you switch to outside air, you'll draw in whatever odors might be outside. Not much you can do about that except to move somewhere where there are no other cars and no odors.

spearenvoy · March 15, 2005

Could this be more of a rather loud click, like a solenoid, rather than a knock?

Not sure what kind of odor you mean. If you switch to outside air, you'll draw in whatever odors might be outside. Not much you can do about that except to move somewhere where there are no other cars and no odors.

<{POST_SNAPBACK}>

It could be more like a loud click or perhaps like a "clack" but it only does it when cold. It goes away after about 10 minutes of driving. The engine temp achieves normal operating temp at about 5 minutes and this noise keeps going for another 5-6 minutes more. It is anoying. My sister has another 2004 envoy and does not have this noise so I know it is not normal. It does not appear to affect the performance of the engine though. Any help is appreciated.

The odor is quite peculiar. It does it only when I start the car and last a few seconds and only when the recirculating button is off. Once I get moving it stops

Thanks

GM-Tech · March 15, 2005

It could be more like a loud click or perhaps like a "clack" but it only does it when cold.

We have issues with the solenoid in the fan clutch (which is electrically controlled) clicking loudly and rhythmically when first started. To see if this is the problem, disconnect the fan connector while it's making the noise. If it goes away, it's the fan clutch. The connector is right at the top of the radiator on the driver's side.

The odor is probably due to bacterial growth on the ac evaporator. We have issues, and fixes, for that too.

spearenvoy · March 19, 2005

It could be more like a loud click or perhaps like a "clack" but it only does it when cold.

We have issues with the solenoid in the fan clutch (which is electrically controlled) clicking loudly and rhythmically when first started. To see if this is the problem, disconnect the fan connector while it's making the noise. If it goes away, it's the fan clutch. The connector is right at the top of the radiator on the driver's side.

The odor is probably due to bacterial growth on the ac evaporator. We have issues, and fixes, for that too.

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Thanks GM Tech,

I tried disconnecting the fan clutch connector but no fix. The tapping noise seems to come from inside the engine towards rear. It is not the typical vlavetrain clicking.

Do you work for a dealer in South Florida. I am in Miami. If you do, maybe I can take it to the dealership you work with.

GM-Tech · March 19, 2005

I tried disconnecting the fan clutch connector but no fix. The tapping noise seems to come from inside the engine towards rear. It is not the typical vlavetrain clicking. Do you work for a dealer in South Florida. I am in Miami. If you do, maybe I can take it to the dealership you work with.

Okay, that eliminates the fan clutch. Yes, I'm in Miami, but I work at a Chevy (only) store. You have a GMC which means we cannot perform warranty work on it. If you'd like to come by for me to listen to see if I can tell you anything just by listening, for whatever that's worth, I have no problem with that.

On the other hand, if it goes away after 10 minutes of driving, the noise probably wouldn't be present by the time you got here, unless you live REAL close.