AC compressor squeal

erkme73 · Jun 14, 2018

Two troubleshooting posts in a row! When it rains, it pours. Just waiting for the third problem to pop up...

As ambient temps got above 80ｰ, I started using the AC. When I shut the engine off, and restart it within a few minutes, if the AC switch was left on, the AC belt would start to immediately squeal. If I turned off the AC switch, the squealing would stop. I could turn it back on again, and the AC and it wouldn't squeal again for the duration that the engine stays on. Unfortunately, over the last week or two, it started squealing at random times.

I checked the tension on the belt and it had some play - so I tightened it up just a bit more, and the squealing has completely stopped. For the last two or three days, with temps in the high 80's, it hasn't squealed once - until today.

The tensioner pulley does have some wear (it appears to be twice as wide as the actual belt), but the bearing is firm (no play). The AC cools very well. However, at this point, I'm not sure if I should tighten the belt a bit more, or toss in the towel and call for service.

I'm reasonably familiar with how AC systems work and their components, but I don't have any gauges, vacuum pump, or replacement refrigerant. Nor do I have the proper experience to confidently start troubleshooting.

What do the resident AC experts recommend? Use small words and speak slowly, please

RNeumann · Jun 14, 2018

If the belt has squealed is has glazed over and will only slip more and more. If you can replace the belt you will have more than likely solved the problem.
Belt dressing or other chemicals only work for about 30’....don’t waste your time or money.

PILOON · Jun 14, 2018

Whenever a belt driven device squeals it generally is due to a slipping V belt.
A worn (read glazed) belt will generally do that.
Belt dressing might cure the squeal but B4 calling service why not simply install a new belt?
Over time belts get glazed and slip and squeal.

erkme73 · Jun 14, 2018

Thanks for the suggestion. I can certainly do that, and that may well be the next step. My concern is that by reducing the slipping, I'm only concealing a bigger problem that might get worse. If I replace the belt and the problem is a seizing compressor, or low/high oil/refrigerant level, will I not do more harm? If not, I'll get a belt tomorrow.

oosik · Jun 14, 2018

What RNeumann said ++. However, I have used a spray belt dressing successfully. Stoped belt squeal for a year - respray the belt every spring. Finally after six years - belt broke and was replaced. This was on my 1982 Troybilt Horse rototiller.

Best way to fix your problem - as RNeumann indicated - replace belt.

RNeumann · Jun 14, 2018

I think that’s over concern. Replace the belt and enjoy the cold air.

Oldoak · Jun 14, 2018

RNeumann said:
I think that’s over concern. Replace the belt and enjoy the cold air.

:thumbsup:

Harry in Ky · Jun 14, 2018

I won't dispute the possibility of a worn(or somehow defective) belt as a contributor to pulley squeal. On the other hand, even a properly adjusted belt in relatively good shape can be over taxed. Since you don't have access to pressure gauges, I suggest you check again for restriction through the condenser and radiator. If your tractor has those silly screens in front of either (or both), take them off. Just a casual "look/see" in therewith them in place won't always tell you the whole story. Get an air nozzle with a wand that blows air at a right angle and go over ALL the cooling coils. Using the wand you can force air between the fins and tubes, not just across the front. Spend some time at it, and cover as much area as you can. When I do this, it can take twenty or thirty minutes but can surprise you with how much dirt and fluff comes out. If this is what you find, the belt is probably not the problem.
As a side note, if it were me I'd put the screens on a shelf somewhere, and not back on the tractor. The stuff I find in the fins went right through the screen anyway.

RNeumann · Jun 14, 2018

All maintenance items for a system that isn’t blowing cold........OP states his system is blowing cold.

erkme73 · Jun 14, 2018

I'll take this as a mid-season reminder to blow out the radiators/exchangers. I'll head to town tomorrow to get a replacement belt. And just to show how wet-behind-the-ears I am, does the A54 on the belt tell me everything I need to know to hit an auto store? A quick search on Google reveals belts that look the same, and all seem to have a 54-56" length...

jamesbrass · Jun 15, 2018

My AC compressor would occasionally squeal. Checked the belt and everything seemed fine. Then it threw the belt off. Dealer replaced the compressor last week.

Gary Fowler · Jun 15, 2018

Harry in Ky said:
I won't dispute the possibility of a worn(or somehow defective) belt as a contributor to pulley squeal. On the other hand, even a properly adjusted belt in relatively good shape can be over taxed. Since you don't have access to pressure gauges, I suggest you check again for restriction through the condenser and radiator. If your tractor has those silly screens in front of either (or both), take them off. Just a casual "look/see" in therewith them in place won't always tell you the whole story. Get an air nozzle with a wand that blows air at a right angle and go over ALL the cooling coils. Using the wand you can force air between the fins and tubes, not just across the front. Spend some time at it, and cover as much area as you can. When I do this, it can take twenty or thirty minutes but can surprise you with how much dirt and fluff comes out. If this is what you find, the belt is probably not the problem.
As a side note, if it were me I'd put the screens on a shelf somewhere, and not back on the tractor. The stuff I find in the fins went right through the screen anyway.

Sure you blew out some chaff that got thru the screen. But how much did it catch? I would never recommend leaving out the radiator screens because a little bit of small stuff got thru.

R134a · Jun 15, 2018

+++ Agree with others. Probable the belt is glazed. Clean they pulleys and install a new belt. Panic when it blows hot air !:thumbsup:

erkme73 · Jun 15, 2018

jamesbrass said:
My AC compressor would occasionally squeal. Checked the belt and everything seemed fine. Then it threw the belt off. Dealer replaced the compressor last week.

Ugh, that's not very compelling. Well, I spoke with the local dealer, and at first the recommended I bring it in to have the system checked. When I told them I had to go buy a trailer to get it to them, and that you guys here recommended changing the belt first, they said that it makes more sense to try the belt approach.

I also have a leaking "oil comp cooler" (posted about it here), and am looking at replacing that myself once I get the part in hand. Pretty sure that was self-inflicted damage. I had a tree branch come up under the cab and lever itself between a filter and a metal supply pipe. That pipe yanked on the cooler under the hood.

Mark_D · Jun 17, 2018

My 2555 had the same problem when I bought it new. I would tighten the belt and it would stop for a while. Then the belt would stretch some more. Did this about 5 times. Then I noticed some cogs had broken off of the belt as well. I will chalk this one up to a cheap belt from the factory. I went to the auto parts store and bought another belt. Haven't had a problem since.

darmstrong2319 · Jun 17, 2018

I have a question for you folks with the 30 -55 hp cab tractors. Does the air conditioner do it’s job when its 90 - 100 degrees F outside? Does it keep you comfortable? Thanks

erkme73 · Jun 17, 2018

Mine has to be blowing on me but it's plenty cool I'm direct sun when 90+ outside.

darmstrong2319 · Jun 17, 2018

Been thinking about a cab tractor but was unsure of ac, didn’t want to buy something and it not be what I need. Thanks

Mark_D · Jun 17, 2018

The HST tractor puts out a lot of heat. On a 90 degree sunny day it won't get super cold in the cab, but it's not uncomfortable. I've been kicking around the idea of getting the windows tinted, as I think that would help a lot.