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Strange chrip from engine bay... AC?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=23377		 Page 1 of 1
Author:  GoghUA [ Sun Aug 12, 2007 9:46 pm ]
Post subject:  Strange chrip from engine bay... AC?
Last week, my wife started notice a strange chirping coming from her engine. The CEL is not on. It only happens when at idle with the AC turned on and it was happening all the time so we took it to the dealer. The dealer was quick (almost too quick, I don't really know how much diagnosis they did) to say that it was the accessory belt. They called to let us know that this is what they "thought" it was, but were certain to specify that they didn't know for sure if this would fix the problem. So, they ordered the part and the next day it is "fixed". Well, when they drive it out for my wife to pickup, it is still making the sound. The tech notices the sound right away and says let me take that back there and look at it again. So, after about an hour of waiting, it was clear they didn't really know what the problem was much less how to fix it. I suggested taking it elsewhere so my wife got a refund and was on her way. I did get a copy of the receipt and the part number of the belt they replaced is 5072437AC. We had planned on taking it to a different dealer, after confirming when their diesel mechanic would be available, but the Jeep has since stopped making the noise on a regular basis and now does it only occasionally when idling with the AC turned on. I am hesitant to take it in now because I cannot readily reproduce the problem. I even tried to get a recording of it to post on here, but no luck...

Anyway, I was hoping someone on here might have some suggestions for how to diagnose the problem?

Thanks!
Author:  Endurance [ Sun Aug 12, 2007 11:41 pm ]
Post subject: 
Hey I think I got the same issue, mine sounds more like a belt squeaking though and it only happens for a second or two when start the vehicle. Mine also idles slightly rough, like a pulley or something is bad. Right now I am hesitant to take it to the dealer because it is not very noticeable.

The more accessories are on the rougher it idles (relatively speaking because it is barely noticeable) , AC, headlights......

Anybody else?
Author:  BlackLibertyCRD [ Sun Aug 12, 2007 11:47 pm ]
Post subject: 
The A/C clutch can squeak a little when it kicks on and off. It metal to metal held by a magnet coil.
Author:  GoghUA [ Mon Aug 13, 2007 6:57 pm ]
Post subject: 
Endurance wrote:
Hey I think I got the same issue, mine sounds more like a belt squeaking though and it only happens for a second or two when start the vehicle. Mine also idles slightly rough, like a pulley or something is bad. Right now I am hesitant to take it to the dealer because it is not very noticeable.

The more accessories are on the rougher it idles (relatively speaking because it is barely noticeable) , AC, headlights......

This sounds isn't so much like a belt squeeking although it is close. Also, once it starts doin it, it seems to keep doing it until I give it some throttle. However, once I left off the throttle and it goes back to idle, it may or may not keep doing it. You also mention a rough idle, I would say that the idle is slightly rougher than normal when it makes this sound, almost like your washing machine being out of balance. I have not noticed it being any rougher as more accessories are turned on.


BlackLibertyCRD wrote:
The A/C clutch can squeak a little when it kicks on and off. It metal to metal held by a magnet coil.

If this were the noise, I assume it would go away rather quickly?
Author:  MACKJ [ Mon Aug 13, 2007 8:20 pm ]
Post subject: 
[quote="GoghUA
This sounds isn't so much like a belt squeeking although it is close. Also, once it starts doin it, it seems to keep doing it until I give it some throttle. However, once I left off the throttle and it goes back to idle, it may or may not keep doing it. You also mention a rough idle, I would say that the idle is slightly rougher than normal when it makes this sound, almost like your washing machine being out of balance. I have not noticed it being any rougher as more accessories are turned on.[/quote]

If it is idling "rougher" it seems more likely there is an increase in mechanical load. My limited experience says the AC clutch would be a more consistent noise. Have a listen around the alternator pulley. You have a small one way clutch inside the pulley(called a decoupler) and they have been known to fail, engaging/disengaging before they head south.
Author:  Timmaah! [ Mon Aug 13, 2007 8:21 pm ]
Post subject: 
In my case it was the accessory belt tensioner. If you look at the tensioner with the engine running you will see that minor imperfections in the drive and driven pullies will conspire to move the tensioner a bit and you may even see the movement coincide with the chirp. It will not mover much, but enough to produce a chirp at a certain temperature and movement that can be enhanced by having the air conditioner on, or load from other accessories. It’s tight quarters in there where I managed to spray some WD40 in the right spot so the chirp stopped – some time ago actually. I forgot about it but expect it to come back some day. Anyway, you want to be very careful spraying oil in there so that you don’t get ANY oil on the drive belt. Of course, you do this without the engine running. :wink:

You could just ignore it and it might go away. The problem is that if it is chirping it is probably binding and may eventually stick and put undue stress on the belt because it is not moving freely. When I do my first serpentine belt replacement I will remove the tensioner to clean and oil it properly. In fact, I was just looking under the hood last night thinking about how to change the belt.
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