Mike Brichta Posted April 13, 2011 Share Posted April 13, 2011 I believe my AC compressor is making a strange noise. I'm pretty sure it is the AC compressor because when I remove the AC belt, the noise goes away. The noise sounds like I have a blower on the car (like metal gears turning) and I hear the noise when the AC is off or on. I am guessing that the bearings in the front of the compressor need to be replaced. AC is ice cold. Thoughts? Question: Can this be repaired on the car or do I have to loose the freon (R12) and remove the compressor to repair? Thanks!! Mike Quote Link to comment Share on other sites More sharing options...
JOHNA01374 Posted April 14, 2011 Share Posted April 14, 2011 Mike, I thought the same thing about my power steering pump last week. it was making a god awful noise that sounded like the bearing was gone. I removed the belt and the pump turned smoothly with no noise so I put the belt back on and checked the other accessories. Turns out the noise was coming from the power steering after all but it turned out to be the belt and not a bearing at all. A quick check for this is to to start the car and use a can of WD40 with the straw. Point it at one belt at a time and give it a quick squirt. If the noise goes away you know it's nothing more than a belt problem. Any kind of spray lube will work fine for this as well as Dish soap if that is all you have but a single drop is all you need. Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted April 14, 2011 Share Posted April 14, 2011 A crayon on the belt will quiet it down as a temp check Quote Link to comment Share on other sites More sharing options...
Mike Brichta Posted April 14, 2011 Author Share Posted April 14, 2011 Well I can always give it a try and see what happens. Thanks!! If it is the compressor do I have to disconnect the R12 Line to have repaired? Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted April 14, 2011 Share Posted April 14, 2011 Yes I do belive so, but isnt there a bearing in the clutch plate on the front see how much play there is in that if any. Quote Link to comment Share on other sites More sharing options...
wallaby Posted April 14, 2011 Share Posted April 14, 2011 When the AC is OFF the pulley runs on a bearing, and when the AC is ON it runs on a different bearing...so there are two bearings in the front of your compressor; one one is used when the entire assembly is rotating (on), and one bearing only used to let the pulley roate freely on the nose of the compressor (when the AC is off). The point I'm trying to make is that if it were a bearing noise, it should change when the compressor is turned on/off, as no single bearing is used in both conditions. You stated that the noise is the same regardless of whether the unit is on or off, so in my mind this means that either BOTH bearings have the same exact noise, or it's not a bearing problem at all and your noise comes from something else. I'd bet the odds that it's something else. If you needed to pull your compressor, you need to disconnect the hoses. You can have a local shop exacuate your system first and record how much freon was pulled out...then have them put it back in after your compressor change. At least that will save you the cost of several pounds of freon. Oh, and the front (idler) bearing on the compressor can be changed without releasing freon from the system, but the rear (drive) bearing can not. Quote Link to comment Share on other sites More sharing options...
Mike Brichta Posted April 14, 2011 Author Share Posted April 14, 2011 Ah, that's what I was looking for. Thanks for the great explanation. At least I understand it enough to talk about it to someone. I played around with it some more last night and tried to listen to the noise while the AC was ON and OFF. The noise is really loud when AC is off and car is idling. As I increase the RPMs or turn the AC ON, the noise gets much quieter. So I am guessing that it is the "front idler bearing" and since I can replace that one while the compressor is still on the car I will try that first. Thanks!! Mike Quote Link to comment Share on other sites More sharing options...
wallaby Posted April 15, 2011 Share Posted April 15, 2011 You can also try using a long screwdriver or piece of broom stick to listen to suspected areas while the engine is running. Press one end of the tool against the compressor just behind the pulley for example and put you ear to the other end. Obviously you want to be careful, but it will enable you to hear all the wonderful noise going on in that spot. You'd be surprised how much noise goes on in a good water pump or alternator; a bad bearing will be obvious. Quote Link to comment Share on other sites More sharing options...
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