LSU Jeeper

Hey Everyone,

2008 JK Unlimited. Last week my A/C stopped cooling, so I took it to my shop and they swapped out the Evaporator Core. I picked the Jeep up yesterday, and the air is cooling now, but behind the dash I am hearing a "hissing" kind of noise about every 30 seconds like clockwork. It sounds like the evaporator is sucking for air or something along those lines. I called the shop and they couldn't tell me what it might be, so before I drive back over there, I need your help educating myself on what the issue may be.

Thanks!

JeepaRoo

a slight bit of hissing will be heard each time the compressor engages.. it is usually normal.. although it can indicate just a slight bit low on charge some cars do it when they are fully charged.

-Christopher

LSU Jeeper

Thanks Christopher. The issue I'm having is that the noise is fairly loud. It gets up over the radio and is really annoying.

The air is cold, but the noise is new. I took it back to the shop and they agreed it was really odd. They actually replaced the evaporator again and it's still happening. They said it might just be the sound of the adtermarket evaporator working, and they don't know what else to do.

Has anyone heard of this?

kik

I've had this with older A/C systems, but not with my JK. It's most likely the new Evap. Sometimes aftermarket parts are not what you want to use with certain JK systems. It's almost worth spending extra for Mopar replacement parts. Other than evacuating and charging the system again, the only cure might be the Mopar part. When the compressor cycles you're getting the noise which would be normal. The amount of noise isn't.

LSU Jeeper

Thanks for the insight. I suppose I will have to hold the shop responsible and get them to replace the Autozone part for an OEM part. It's strange to me that the mechanic was clueless and had no insight into the problem - maybe he was avoiding having to get the OEM.

'11BronzeStar70th

I had the same hissing sound with my '11 and the dealer kept telling me they A. Couldn't hear it, or, B. It was normal. I didn't have any work done on my system but it seemed to start in the fall of '13 when I started using my defroster. The next spring, I gave it one more shot with the dealer and had the tech get in the cabin with me while the sound was audible. He checked the level and said it was OK. On the way home, I stopped by Autozone and picked up a recharge kit with a gage and put about 2/3 of the can in and the sound hasn't returned.

It's worth the few bucks to try it out. Make sure they double check all the connections first!

Chadc880

Yes same here on my 12 JKU freon leak at condenser causing a slow leak in turn caused the loud hissing sound every time the compressor turned on.

Dealer confirmed JK's make this noise if freon is low ??!!!

LSU Jeeper

Thanks for the reply. They keep telling me it's fully charged, but my gut said the same thing. Seems like it may just be low. And check this out - I just picked up the jeep - AC is still hissing, rear windows won't roll down (not connected I'm sure), and I have water coming in under the passenger dashboard when I drive through wet conditions (or a carwash)... WTF.

mzj95

LSU Jeeper

I had the shop swap the compressor with the OEM part and the noise reduced by about 70%. It's been 3 years and it still hisses a little bit, but blows ice cold every day, so i've just learned to ignore the sound. Hope that helps.