Loud clunk when engaging a/c compressor

[hearno]

I recently had my a/c recharged - it was blowing cool (38 deg at center vent) but I got the dealer I bought it from to do it for free. Since the recharge - it still cools fine but the compressor makes a noticeable clunk when it engages. Pretty much only after the car has been sitting for a while. I also noticed a sucking/hissing sound from the dash when the a/c is first turned on after the car has been sitting for a while. Anyone have any insight?

 

[ghs215]

From what I understand....

The clunk sound is probably the clutch engaging. Could mean the clutch is on its way out?

The hissing is the refrigerant going through the expansion valve. Usually due to when the compressor kicks off and the AC refrigerant is equalizing. Think of the expansion valve as a stopper with a little hole in it.

Hope it helps.

 

[rja4z3]

Hearno, did you ever find out what the clunk was? Is it the clutch going out? I've got the same issue.

Edit: I just found this on TacomaWorld - "Happens when the refrigerant condenses and collects near the inlet port of the compressor. When the compressor kicks on for the first time after a period of sitting, the condensed refrigerant slams into the compressor making that noise. Not exactly healthy, but perfectly normal on these trucks."

Anyone know if that's correct?

 

[hearno]

Hearno, did you ever find out what the clunk was? Is it the clutch going out? I've got the same issue.

Edit: I just found this on TacomaWorld - "Happens when the refrigerant condenses and collects near the inlet port of the compressor. When the compressor kicks on for the first time after a period of sitting, the condensed refrigerant slams into the compressor making that noise. Not exactly healthy, but perfectly normal on these trucks."

Anyone know if that's correct?

Interesting... mine wasn't doing it prior to a recharge but definitely is now. I'm having it looked at tomorrow and will let you know what I find.

 

[JacksonRally]

Mine does this. I hear 3 consecutive "clunks" when I start the engine with a/c in the on position. Every day, every time I start the engine. A/C blows cold and has yet to let me down so I am running with it.

 

[toyo]

I would have the pressures checked just to make sure. An overcharged system can do this as well.