Squeal with A/C on

mvoss15 · **Posted:** Sun Jul 29, 2012 9:25 pm

Today our CRD started giving off a fairly loud squeak or squeal whenever the Air Conditioning is on and the compressor engages. Turning A/C off and the noise goes away. Today was 106 degrees here in Arkansas, and probably the hottest day that we've driven this summer.

Thinking it is likely either the compressor or an issue with the alternator pulley? The serpentine belt has a noticeable vibration to it below the alternator when the Air is on, appears fine when off.

Any advice? It's way too hot out to try and work on it myself, so I'll probably need to take it somewhere this week.

cgass · **Posted:** Sun Jul 29, 2012 9:28 pm

My first thought would be a pulley. That's a much cheaper fix than a compressor too.

mvoss15 · **Posted:** Sun Jul 29, 2012 9:40 pm

Could a pulley only cause an issue when the compressor is engaged?

cgass · **Posted:** Sun Jul 29, 2012 10:51 pm

Not sure there. You can try checking the pulleys. There's a simple, but slightly dangerous, way to check. If you take a long screwdriver and hold it so its just touching the pulley and then out your ear to the handle end you'll be able to hear the ringing magnified in the screwdriver. That's a good indication if a pulley is bad. *Disclaimer * be careful not to get the screwdriver caught in any moving parts. I'm not responsible for any injuries or damage.

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mvoss15 · **Posted:** Tue Jul 31, 2012 9:26 am

Had some time to check this out further last night. Under normal conditions, with the engine running, should the serpentine belt tensioner appear to stay completely steady, or is a certain amount of movement/vibration considered normal?

Mine's definitely not steady. Using cgass's suggestion, the sound does not appear to be coming from the alternator - perhaps the idler pulley that is in the middle.

cgass · **Posted:** Tue Jul 31, 2012 9:39 am

It should be pretty steady. If its vibrating a lot or moving back and forth across a pulley that's another indication that either a pulley is bad or the belt slipped off of alignment on that pulley. You should be able to see unusual wear on the bottom of the belt

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Big Montana · **Posted:** Tue Jul 31, 2012 11:29 am

I'm pretty sure that a vibrating tensioner is bad. If it's moving, it's not maintaining tension on the belt hence the slippage. It could be possible for the AC to be fine, but once you add the load to the belt, the tension becomes too much for the ailing tensioner to deal with. I would start with replacing that first.

Big Montana · **Posted:** Tue Jul 31, 2012 11:30 am

Oh and how old is your belt?

galatron · **Posted:** Tue Jul 31, 2012 4:50 pm

Squeel with the AC on is more likely the pulley on the alternator, mine did that, and I replaced the pulley.

papaindigo · **Posted:** Wed Aug 01, 2012 6:45 am

There are at least 3 "clutched" (pulleys that are not locked to run something all the time) running off the serpentine belt. Alternator, viscous heater, and AC. As I understand it the serp belt tensioner serves 2 functions 1) to keep constant tension on the belt and 2) to absorb the "shock" of a clutched pulley engaging. So long as the clutched pulleys are working ok the tensioner will barely twitch (not quite dead steady but darn near) as viewed looking down the serp belt from the drivers side with the plastic engine cover removed. If a clutched pulley is bad or going bad it tends to add more shock to the serp belt causing the tensioner to noticably bounce hence causing variation in the amount of tension on the serp belt which is probably the cause of your squeal. Running too long with a bad clutched pulley will cause the tensioner to fail at which point it's not uncommon for the tensioner to lean into the power steering pump pulley, sometimes enough to cause the power steering pump not to work.

Based on prior chat the most common clutch pulley to fail is the one on the alternator - alternator decoupler pulley 53013554AE or Litens 920720 costing about $80, check around on how to remove without special tool or sometimes Advance or Autozone has a lifetime warranty replacement alternator for ca. $150; do not try a Facet reactive alternator pulley as it's not up to the job on the CRD. I've heard of one viscous heater clutch failure (viewtopic.php?f=5&t=60567&start=20); you can disable the viscous heater clutch by pulling the R36 relay in the Power Distribution Center for either model year and see if that helps. If it's your AC compressor clutch that's beyond me.

4x4kingx889 · **Joined:** Sun Jul 17, 2011 6:42 pm **Posts:** 235

I had the same problem it was the alternator pulley I replaced the whole alternator and it fixed my problem and also idled allot smother I would fix it asap because it will also ruin your belt tensioner

junkjeep · **Joined:** Mon Jul 09, 2012 11:03 pm **Posts:** 6

I just went through this. The problem was a weak belt tensioner. If the problem was in the alternator it would squeal any time the engine is running and if the clutched alternator pulley is bad you will most likely have a charging issue as well.

mvoss15 · **Posted:** Thu Aug 02, 2012 5:13 pm

Update - well, sort of. Driving home from work today, I hear an audible "pop" and lose most of my power. Related to this by chance?

Other than power loss, seems to run fine, no loss of oil, everything else is normal. Is it time to order a set of Samco's?

Hopefully will have time to inspect the boost hoses tonight.

Edit - yes, Hose from intercooler back to intake has a 3" split. Time to order more stuff

Squeal with A/C on

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