AC Making Periodic Hissing Noise - JeepForum.com
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post #1 of 9 Old 08-18-2017, 03:44 PM Thread Starter
joshbarnett
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AC Making Periodic Hissing Noise

I have a 2015 GC Laredo. About 2 weeks ago I started noticing a hissing sound coming out of the vents in the front panel when the AC is on. The noise is not constant, it seems to correspond to the compressor coming on and off (with it being at its loudest when the compressor kicks on or off, I can't quite tell). The AC works great - I'm in central Arizona at the height of Summer and it cools no problem. I have done some research and it seems it could be one of two things: expansion valve or refrigerant leak. As for the latter, I think if it was a leak, the AC would have stopped working by now, no? The only problem this truly presents is the sound is pretty darn annoying. So if it is the expansion valve making this sound, what could be done about it?

Thanks.

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post #2 of 9 Old 08-18-2017, 04:06 PM
2008OverlandCRD
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Maybe you have a snake in your dash?
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post #3 of 9 Old 08-18-2017, 04:07 PM Thread Starter
joshbarnett
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Quote:
Originally Posted by 2008OverlandCRD View Post
Maybe you have a snake in your dash?
Conceivable, but highly unlikely.
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post #4 of 9 Old 08-19-2017, 10:20 AM
Jeepdaze
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I had this exact problem on my 2011 Hemi two summers ago. It is an indication of losing pressure in the system and it will start cooling less and less over time. I had to have my condenser replaced and was told that wasn't an uncommon problem on older WK2s.

My wife's 2011 Hemi also had this problem, but she needed a new compressor.

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post #5 of 9 Old 08-19-2017, 10:34 AM
ColdCase
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Yeah, usually these get noisy when losing refrigerant, but not to the point where cooling efficiency is affected. A nice early warning feature

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post #6 of 9 Old 08-19-2017, 11:12 AM
RIPSAW
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My guess is it's normal. If you heard it leaking, it would quit in a day since there is probably not 32oz of R134A in it. It the bleed back from High Head pressure probably at low RPM like at a red light on the lower fan levels. There is a thermal off when it gets to freezing level. That is what turns off the compressor. Like you say, that is just the high-pressure bleeding past the orifice in the expansion valve. If it's dropping water out the drain under the car, it's fine. Both my truck and wife Subie have always done it.

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post #7 of 9 Old 08-19-2017, 11:19 AM
RIPSAW
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My guess is it's normal. If you heard it leaking, it would quit in a day since there is probably not 32oz of R134A in it. It the bleed back from High Head pressure probably at low RPM like at a red light on the lower fan levels. There is a thermal off when it gets to freezing level. That is what turns off the compressor. Like you say, that is just the high-pressure bleeding past the orifice in the expansion valve. If it's dropping water out the drain under the car, it's fine. Both my truck and wife Subie have always done it.

For some reason, Forum will not let me edit above.

Is it cycling too much? Or running out of cool at high speed? If so, it could be low and causing it to freeze too fast.

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post #8 of 9 Old 08-19-2017, 01:08 PM
ColdCase
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While you are in probation, the forum software isn't going to let you edit. I think you need 10 posts.

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post #9 of 9 Old 08-19-2017, 06:21 PM Thread Starter
joshbarnett
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Quote:
Originally Posted by RIPSAW View Post
My guess is it's normal. If you heard it leaking, it would quit in a day since there is probably not 32oz of R134A in it. It the bleed back from High Head pressure probably at low RPM like at a red light on the lower fan levels. There is a thermal off when it gets to freezing level. That is what turns off the compressor. Like you say, that is just the high-pressure bleeding past the orifice in the expansion valve. If it's dropping water out the drain under the car, it's fine. Both my truck and wife Subie have always done it.

For some reason, Forum will not let me edit above.

Is it cycling too much? Or running out of cool at high speed? If so, it could be low and causing it to freeze too fast.
Not running out of cool at high speed. Seems to work totally fine. Compressor comes on and off at seemingly normal intervals. But I will say that when I'm at a light or otherwise stopped, the noise is louder than when I'm driving.
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