clunk / bang (ish) sound from a/c compressor

[formula]

Sometimes, when I start the truck and then turn on the a/c compressor (with the button or by turning on defog) there's a very noticable clunk/bang sound when the compressor kicks on. This has happened I think twice now (I've run the compressor quite a lot). The electric clutch normally only makes a quick little soft click sound. I can't manage to do anything to force it to make the noise, just seems to be by chance that it'll do it. Makes me reluctant to bring it to the dealer only for a "cannot duplicate problem" Has anyone else had this noise? Any ideas of the cause / fix..... or is it even a problem at all?



Sean

 

[rbattelle]

Absolutely normal for these trucks. Mine has done it since day 1.



Link 1



Link 2



-Ryan

 

[formula]

ahhh, I see. Thanks for the info. fwiw, I did do a search first I think the database doesn't like me or something :-laf :-laf



Sean

 

[lil red cummins]

best i can tell from mine, is that because the clutch is metal to metal contact (or metal to metallic clutch), when it sits for a while, it gets a slight rust build up on it.



then when you turn it on, it scrubs the rust off for a split second and then seats completely. i have noticed it is worse as the humidity goes up.



my . 02



good luck



jim

 

[Elk]

I have owned 4 and everyone has done it and i have neve had a failure, It does sound awful though

\

 

[RVTRKN]

I had the same noise

My 04. 5 2500 4X4 cummins from the first day made the same noise. My wife often complained of cool air, not cold air from ducts on her side. I did not believe her until I sat in the pasenger side. I mentioned this to the service writer without mentioning the compressor noise. He knew the system was probably low on refrigerant. It was properly charged and has not made the noise sense. I hope yours is as simple

 

[Heavyweight]

Count mine too. That damned thing sounded like someone through a tire iron into the fan! It has done it 3 times, since purchased new in April.

 

[Shooter]

Yep ! Oo. Oo. :--)

 

[sag2]

My 03 and the 04 do it. Seems louder if it is shut off in warm weather and then started in the cool of the morning. 40,000+ miles on both without a problem.

 

[2Gen3Gen]

My 04 and my 04. 5 have and had the same clunk. NORMAL so says the dealer

 

[Tony T.]

My truck also does the clunk sound, and has since day one considered normal, but every so often I notice a surging from the air vents. This happened just a couple days ago, left work drove about a mile to a signal light,I was setting there waiting for light to change and noticed the surging from high level setting to low level setting serveral times. Once I took off and got to rolling the air flow was normal sounding and normal feel coming out the vents. Why would it do that. I have noticed it on other vehicles I've drove, but didn't know the reason why.



Tony

 

[LightmanE300]

I have the thump too - and no problems yet, but I don't use the a/c that often aside from the summers. I had the same clunk in my tahoe and the compressor went bad at 80k. Not sure what causes it but it's annoying and inconsistent.



My air seems to only be cool at best at idle, and gets cold only once revs/speed go up. Is everyone else's like that?

 

[Heavyweight]

Mega Ditto's Lightman. AC in my truck is pretty close to what you describe.

 

[RVTRKN]

Any replies about ref charge

To all that have the noise, did you have the refrigerant properly checked? The procedure should require recovery of the refrigerant and then (per data plate) weighed in. This is the method used for my truck and as of this date my wife has not complained since.

 

[Subby]

I've never had the 134 checked but I've had the loud clunk on startup since just after new. I swear I'm gonna open the hood and at least find the belt shredded or the compressor hanging by the hoses.

 

[rbattelle]

I swear I'm gonna open the hood and at least find the belt shredded or the compressor hanging by the hoses.

Yup, it sounds that bad. It's so bad I can actually feel it through the floorboards when it happens.



But here I am at 2 years and 46k miles and everything still works fine [knock on wood, cross fingers and toes].



-Ryan

 

[tkerrigan]

I try to remember to push the clutch in and idle the engine when I turn on the AC. I've heard that noise 4 or 5 times and it makes me think of snapping drive belts. Sudden impacts is not one of the things that serpentine belts do well.

 

[Razkul99]

I have found the noise to be loudest if I engage the A/C right after ignition...

 

[RGardner]

My 03 has never cooled like I think it should, the only way that it will really cool is to recirculate the air witht the cooler on high. I thought that maybe the extra room in the cab was the problem but I have a 98 explorer that will cool the whole area much better!

 

[RGardner]

And yes it has made the loud clunking noise! I thought I had run over someones muffler! Scared the **** out of the the first time it happened!