Hey guys. So when I turn my AC on for the first time during my drive, there is a loud grinding noise that last for about a second. The revs drop a little bit and I can feel the Jeep lose some power, but its only for a second. The AC is noisy for about 30 seconds, then quiets down considerably. After the turning the AC on the first time, I can turn it off and back on as many times as I like without any issues. However, once I park the Jeep and it cools down, the next time I drive it the same thing will happen. Is this normal, or has anyone had this happen to them? Thanks!

 

I have had this SAME EXACT thing happen to me 2 or 3 times. However, it seems to have stopped..... It happened like 2 or 3 times exactly how you describe, and then just stopped doing it and worked normally.

I had no idea what it was and when the Jeep nearly stalled from it, I was worried...but it just stopped happening?

Anyone have any input?

 

I had this problem on my previous car. I found that the belt was either loose or has got some oil on it that causes it to slip and make a squeek sound. This might be the prob but i'm not sure if the grind that you hear is like the squeek that i heard.

 

I have the same problem on an 08 Wrangler 4 door. Anytime the jeep sits for more than 24 hrs. I get a "crunch/grind" on startup. It will do it even if the A/C is not turned on. Sometimes it won't do it until I engage the A/C. After that first time it won't do it again on restart until it has been sitting for at least 12 -24hrs.

I had a friend watch under the hood on a startup after 24 hrs. He said the noise is coming from the A/C compressor when the clutch engages. The noise is loud, enough to startle you and passengers ask "what the hell was that?"

I'm trying to figure out a way to leave it the dealer over a weekend so they can hear it on a Monday. It is not a "normal" operating sound. Why does the long sitting induce the problem?

The A/C works fine though I do get a "whining/buzz" out of the engaged compressor around 2000 rpm after the A/C has been running a while and the engine is warmed up.

There are a few other threads here that describe the same thing. But no solution so far.

Rich

 

i have had the same thing happen to me a couple times. does it for a second when starting the engine even when the AC isnt on. guess ill call the dealer tomorrow since now i know its not just me
Allen

 

rloose, you described it much better than i did. it makes me cringe every time that it happens, it just sounds like something is about to break. i will also try to take it to the dealer and see what they tell me. thanks guys!

 

mine did it once, so i took apart the fan box (under the dash, passenger side) it sounded like the fan was hitting something. nothing was broken in the box, so i put in back together. i didn't fix anything, but no noise for over three months.

 

Keep everyone updated guys. Thanks!

 

It sounds like your a/c clutch is rough. This is a machined steel plate assembly attached to the compresser shaft. When you turn on the a/c, current is passed into the ring surrounding the plate, causing it to become a strong electrmagnet. This locks the belt pulley and the compresser shaft together, causing the compresser to circulate the 134a, and you have a/c! Your clutch could have grit in it, a warped plate, mud in it, a bad pulley. Normally a little roughness in a compresser clutch will smooth out with use. Cycle your a/c on and off 5 or 6 times while driving for a week or so and see if that smooths it up.....Remember your a/c works as a drier for interior air, thats why you will hear the clutch engage sometimes and the a/c is ''off''.

 

mine does it.

figured it was just another "bonus feature"