# Cummins AC compressor clicking



## T-N-T (Dec 23, 2016)

2007 dodge cummins 
Clicking almost like a chirping sound while ac is off
Turn on AC and sound stops instantly.

Compressor going bad?


----------



## rayjay (Dec 23, 2016)

Most likely something in the clutch.


----------



## T-N-T (Dec 23, 2016)

I'm going to try and get then freon checked and if that ain't it, well time will tell right.


----------



## rayjay (Dec 23, 2016)

It's probably the bearing in the clutch. When the AC is off the compressor isn't turning but the pulley is. When you turn on the AC the electromagnetic clutch engages and the pulley is locked to the compressor which then spins. The bearing in the pulley is no longer turning when the compressor is engaged. So if the bearing is failing it would make noise when the ac is off and be silent when the ac is on. If the Freon was low the clutch would not engage as there is a pressure switch in the circuit.

Waiting until it fails will probably result in needing a new compressor. There may be youtube vids detailing the repair. Probably a Sanyo compressor.


----------



## T-N-T (Dec 23, 2016)

OK, so that's more of an education than I have ever had in ACs.
It didn't do it the two times I cranked up and drove this afternoon. 
Typical right.


----------



## cowhornedspike (Dec 23, 2016)

It's possible that it is just a belt noise that changes/goes away when under a different load.  Otherwise i agree with rayjay.


----------



## NE GA Pappy (Dec 23, 2016)

check the belt tensioner.  Sometimes they will stop moving at the pivot point and not keep tension on the belt.  

When the alternator or power steering pump changes the load on the belt, it will flex and squeak and chirp. Sometimes they will make a rattling noise.  

While you are checking the tensioner, you can slip the belt off the a/c pump and try turning the pulley by hand. If you feel a rough spot while turning pulley, the bearing is going bad and needs to be replaced.


----------



## T-N-T (Dec 24, 2016)

Thanks guys.


----------



## T-N-T (Dec 25, 2016)

So the noise was a one day thing. Have used truck about 6 times since the noise and no Noise has returned. 
Maybe it was a fluke and the clutch was hung some how that time ???

If the noise repeats itself I will be investigating further.


----------



## Huntsman.45 (Dec 25, 2016)

Most likely a belt chirp. Check your belt for cracks or debris.


----------



## GoldDot40 (Dec 31, 2016)

If it changes with humidity, it's likely the belt. If the noise comes back with a drastic temperature change, it's likely the clutch bearing...but COULD still be the belt. 

One way to check it is to remove the belt and turn the compressor clutch pulley with your hand and feel for 'roughness' while spinning it. Also check the tensioner while you have the belt off.


----------



## T-N-T (Dec 31, 2016)

So, I had a buddy look at it who is a mechanic.  
He found some gunk on tensioner pulley.  We think it got a few drops of oil from the puke tube coming from crank case vent.
The noise came after a bunch of short trips that didn't get things hot.
After a long ride and everything getting up to temp good I have not heard it again.

I'm hoping that when I take a wire brush to the moving pulley (sounds safe huh!) And move the puke tube back to the rear of the engine compartment, all will be normal


----------

