01 Forester, 218k miles. I hear a whining noise that appears to come from the A/C. It makes this noise even with the A/C off, though the noise intensifies with it on.

The A/C still blows cold air.

Do you think it's the compressor dying, or a bearing going bad... if it's a bearing would I need to have the compressor replaced? And what kind of costs am I looking at?

Just to make sure that I'm understanding correctly, the noise is coming from the engine compartment?

 

There are more than a few sources of noise near the AC compressor. Take the belt off and spin each pulley by hand to see if any have play or feel rough.

If making noise when A/C is turned off, then it must be in the clutch unit at the front of the compressor. Suspect the bearing in this unit is going bad, so compressor unit prolly still works okay, and I bet is still pumping out cold air.

 

Years back I had a similar problem on a VW. I just replaced the clutch unit, which is right at the compressor belt pulley to fix the problem. The compressor unit did not have to be replaced from the car to do the work, so there was no loss of refrigerant.

 

I bet you could snare a clutch unit from a wrecking yard without much difficulty.

 

Update: Subarupartsforyou.com sells pulley assembly AC idler for $22.

Edited October 12, 200916 yr by Rooster2
update.......more info

Thanks Rooster, does anyone know of online instructions on replacing the A/C Idler Pulley?

 

I will probably have to take it in unless it's something easy for me to do and I am worried the mechs will try to insist replacing the compressor even though it is blowing cold air.

If it still makes the noise when the compressor is engaged then the compressor is also bad.

The pulley rides on it's own bearing separate from the actual clutch. When the clutch is engaged the pulley is locked to the shaft of the compressor. The bearing on the pulley is no longer spinning at that point. Therefore, the noise should stop if that bearing is the source of the noise.

 

I would suspect, since it's in the same area, the tensioner pulley for the AC drive belt. The tensioner pulley spins on its own bearing at all times when the engine is running, and is placed under higher load when the compressor is engaged. It's also a hell of a lot easier to replace.

If it still makes the noise when the compressor is engaged then the compressor is also bad.

The pulley rides on it's own bearing separate from the actual clutch. When the clutch is engaged the pulley is locked to the shaft of the compressor. The bearing on the pulley is no longer spinning at that point. Therefore, the noise should stop if that bearing is the source of the noise.

 

I would suspect, since it's in the same area, the tensioner pulley for the AC drive belt. The tensioner pulley spins on its own bearing at all times when the engine is running, and is placed under higher load when the compressor is engaged. It's also a hell of a lot easier to replace.

 

How can I test which one it is?

 

If it's the AC drive belt pulley, how do I replace it or is it a job I should take it to a mechanic to do?

 

edit - my friend who listened to it said he thinks it is the bearing not the pulley itself. make sense?

Edited October 12, 200916 yr by subegrl

plant sprayer with water, see if the noise changes by isolating sources

 

or turn the radio up and drive on until it seizes, then you'll know for sure

How can I test which one it is?

 

If it's the AC drive belt pulley, how do I replace it or is it a job I should take it to a mechanic to do?

 

edit - my friend who listened to it said he thinks it is the bearing not the pulley itself. make sense?

 

 

Use a very long screw driver as sort of a stethoscope. Touch the end of the screw driver on the bolt head (or very near by) the suspected bad bearing, then touch the other end to your ear, or side of your head. The sound traveling up the screw driver will be a lot louder where the problem is. This is an old trick that my dad taught me, when I worked at his gas station many years ago. I know it sound a little dumb, but this technique works really well. Of course you do this while the engine is running. Just be careful not to let that screw driver slip out of your hand while moving it around those moving pulleys and belts.

 

Agree with other poster, it could well be your belt tensioner. I have replaced those when the bearing goes bad, and starts making noise.

Listen with a mechanics stethoscope, or the screwdriver method. Or you can remove the belt and spin the pulleys by hand (engine off) and listen for noise and check for play or wobble in the pulley.

 

Yes, it is the bearing that makes the noise, not the pulley itself, but unless you have a press it's easier/cheaper to replace the whole thing as an assembly. The AC clutch pulley will need some special tools to replace. The idler/tensioner pulley is one bolt, very simple.

Listen with a mechanics stethoscope, or the screwdriver method. Or you can remove the belt and spin the pulleys by hand (engine off) and listen for noise and check for play or wobble in the pulley.

 

Yes, it is the bearing that makes the noise, not the pulley itself, but unless you have a press it's easier/cheaper to replace the whole thing as an assembly. The AC clutch pulley will need some special tools to replace. The idler/tensioner pulley is one bolt, very simple.

 

Think I borrowed a smaller puller from AutoZone, when I replaced the A/C clutch pulley on my VW years back. Seemed easy, don't remember the R&R being much of a project. Still remember that I did not have to remove the compressor from the system, forcing an evac and recharge of refrigerant.

What exactly is the part that consists of the AC drive belt tensioner pulley on subarupartsforyou.com? Because if it's one bolt I figure I could give 'er a shot.

The tensioner pulley is the one that puts tension on the belt so it doesn't slip. If you go look at your engine, it's the one directly under the compressor.

 

The idler pulley is number 1 in the picture.

Is the tensioner pulley in this picture? If it is I can't figure out which one it is.

 

If it's not , does anyone know the part number so I can order it?

 

Thanks so much everybody.

Is the tensioner pulley in this picture? If it is I can't figure out which one it is.

 

If it's not , does anyone know the part number so I can order it?

 

Thanks so much everybody.

 

 

73131AC010

 

 

 

this fits a 97 outback. probably the same for all 90 - 99 and beyond.

 

i may have the bearing, i sold gary one for his H6 and again i'm betting they are all the same. but by the time you identify it and match it up with mine, you probably could have bought it, installed it and tackled another problem.

A friend and I just checked and he says it is the idler pulley. I have one ordered. Thanks so much guys!

 

I have the new a/c idler pulley. Does anyone have instructions on how to replace it? What wrenches will I need? Thanks.

An assortment of Metric wrenches and sockets as well as a 3/8" ratchet and a 3" drive extension.

Release the tension on the belt by loosening (not removing) the lock nut on the tensioner assembly, (on the picture above it is part number 5) then turning the adjusting bolt clockwise until the belt can be removed.

Once the belt is removed the lock nut on the adjuster can be removed and the pulley should pull off from the back of the adjuster. Be sure to note the orientation of the pulley. (it may be shaped differently on one side than on the other and will throw off the alignment of the belt of the new one is not installed the same way) Remove the bolt from the center of the bearing and put it in the new one.

Installation is the reverse of removal.