2nd Gen Non-Engine/Transmission Intermittent mystery "clunk" when A/C comes on

[WKener]

Hey guys, I have a noise that I am unable to figure out. When I start the truck after it's been sitting for 6-8hrs, and I first turn the A/C on, lately I have been hearing a "clunk" or a "pop" from what seems to be directly under the passenger seat. There is about a 1-2 second delay from when I click the A/C knob until I hear the clunk (well after the a/c compressor clicks on, too). This does not happen every time I turn on the a/c, only after the truck has been sitting for hours... And it doesn't always happen even then. I would estimate I hear the noise once every 2-3 days (upon morning startup).

Does anybody have any idea what I am talking about?? Have any of you run into a/c problems that involved symptoms like what I am describing?

BTW, the a/c still works fine, I am just wondering if this could be a sign of things to come... Maybe some preventative maintenance is in order.

Thanks guys,

Wes

 

[Phil Stuart]

Sounds like it is the........

A/C compressor clutch engaging on first startup. My '01 did the same thing from time to time and once I figured out what it was I really never worried that much about it. Didn't have any problems.



Phil

 

[kluther]

i replaced my drive belt (daco) took care of the problem

 

[The patriot]

I was kind of thinking along the lines of...

The heat/cooling box dampers moving after the loss of vacuum over night.

Eric

 

[WKener]

Thanks for the replies guys, I will check dampers today. I just replaced my belt at 90K miles (~107K now), so I don't think that is it...



Wes

 

[The patriot]

Keep us posted. When it happens to mine, I want to know where to look.

Eric

 

[rraulston]

its a vacuum operated door inside where the evaporator is located. mine does the exact same thing. Sometimes scares me it slams so loud. ignore it... . RRR