Grind when turning on AC
10-17-2008, 05:03 AM
#11
JK Enthusiast
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That's what it is...it is a feature added to nock the mud dubbers nest loose frome the AC compressor...At least thats what I tell myself. Mine does it too so it seems to be a common probem. I am not planning to worry about it till the AC craps out.
10-17-2008, 05:17 AM
#12
JK Newbie
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Mine didn't do it when brand new but has started to do it at 500 miles. I have heard it in other cars I have owned. Seems like when sitting overnite, dust and/or humidity collects on the cold belt and the sudden shock of the compressor load as it turns on causes the belt to shudder before the tensioner can take up the slack.
A warm belt will be more pliable and is less likely to make a noise. That is why it only happens with a cold engine. Annoying, but nothing to lose sleep over.
A warm belt will be more pliable and is less likely to make a noise. That is why it only happens with a cold engine. Annoying, but nothing to lose sleep over.
10-18-2008, 09:03 AM
#13
Guest
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Could not duplicate the problem
I took my Jeep to the dealer and they "could not duplicate the problem". This particular dealer is notorious for this approach to solving warranty problems. They are far more pro-active at fixing things out of warranty on your dime. They have no concept of troubleshooting. The technician merely checked the A/C air temp and said it was in specification. I showed them the whining noise coming from the compressor but they said that was normal. Odd that I didn't hear it when the Jeep was brand new. I think it is a bearing going out or maybe the compressor clutch is slipping a little?
So I purchased a gauge kit at AutoZone and measured the low and high side A/C 134a pressures. They are at the acceptable low end. One thing I did notice is that when the clutch is not engaged, the low and high pressures equalize to about 100 psi. Is this normal?
Rich
So I purchased a gauge kit at AutoZone and measured the low and high side A/C 134a pressures. They are at the acceptable low end. One thing I did notice is that when the clutch is not engaged, the low and high pressures equalize to about 100 psi. Is this normal?
Rich
10-20-2008, 04:57 AM
#14
JK Super Freak
more than likely you have a little liquid refrigerant / oil make its way back to the compressor's compression chambers when the Jeep sits for a while, so the first time the compressor engages it will "Slug" a bit till it itself free of the liquid 134a or oil... it has to do wit hthe refrigerant runback from the evaporator core... when the Air-conditioner is in use the refrigerant doesnt have a chance to settle and underhood temperatures are high enough that more of it is gas than liquid.. when the jeep sits and coold down some of it will condense back to liquid and end up in the compressor... they used to Use accumulators for this purpose... shouldnt hurt anything... my A/C compressor whines a little in my Jeep also.. A/C seems to work normally (that is when my engine cooling fan actually comes on without burning up)
-Christopher
-Christopher
10-20-2008, 05:46 AM
#15
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A/C noises
Jeeparoo-
Thanks for the info. I paid my $15 to one of the "just ask the expert" mechanics on line. He said the same thing that you just posted. Oil will pool in the compressor and "slug" on startup. He said this was a "normal" and happens on many Chrysler products. I wonder if there is maybe a little too much oil in my system. Also, there is a vertical black cylinder visible to the left of the radiator faced from the front. I thought it might be an A/C accumulator.
Rich
Thanks for the info. I paid my $15 to one of the "just ask the expert" mechanics on line. He said the same thing that you just posted. Oil will pool in the compressor and "slug" on startup. He said this was a "normal" and happens on many Chrysler products. I wonder if there is maybe a little too much oil in my system. Also, there is a vertical black cylinder visible to the left of the radiator faced from the front. I thought it might be an A/C accumulator.
Rich
10-20-2008, 11:23 AM
#16
JK Super Freak
id have to look in the Jeep docs to see what that cylinder is however a true accumulator is located on the suction (low pressure) side of a system... the assumulator was designed to catch unevaporated refrigerant in an orifice tube system... with a TxV you shjouldnt have much lf any liquid return to the compressor... but when system settled esp overnight when its cooler out you will end up with some in the compressor.. esp since on our jeeps the compressor is not mounted at the highest point in the system... it is down low.....
-Christopher
-Christopher
10-21-2008, 02:17 PM
#17
Mine does that ,it's an 08 with 15000 on it already. i think it sounds like liquid in the compressor. Having been around large refrigeration machines for a while that's what comes to mind.Not always but sometimes it does it.
10-23-2008, 07:50 PM
#20
JK Junkie
its just the compressor getting oil recirculated back thru it, Basicly a dry start up. Just get going down the street before you turn the A/C on, shlould lessen the rpms from dragging down and possible stalling the engine. You should here my 91 lexus ls400 make A/C noise.
Couldn't resist- don't take it too serious, my daughter and son-in-law have 2 of 'em, I give him Hell. ( he probably hates me...)