AC compressor failing

[Californio]

Hi folks,

About a week ago on a trip my AC started making a squeaking sound when it cycled on, and closer examination with stethoscope confirms that the sounds are coming from the pulley end of the compressor. I'm assuming this is a death knell for the compressor.

I put in Duracool (similar to Redtek) about two months ago after evacuating the system of 134a (had this done by an AC guy.) Duracool/Redtek are supposed to be easier on the compressors in that they reduce head pressures, but could this change have resulted in the compressor failure?

Second, I have a new (used) compressor waiting to go in. Can I just unbolt the old one, let the Duracool escape, install the new one and put in more duracool? Or do I have to evacuate the system again, etc.? Since I only have one can of duracool left it would be nice not to have to mail order more.

The duracool works great. Driving through the Sacramento Valley, , I had a maximum 17* temp difference inside/outside (81 in, 98 out) measured at the top of the B pillar. Probably not too accurate measurements but still good enough.

This is an I4 Tiico conversion with the serpentine belt (A-3) setup.

[tencentlife]

With a squeak on engagement I don't think your compressor section is having a problem so much as the clutch. Despite being sold as a single unit these are separate components and the clutch hub can be removed from the pump and dealt with on its own, although I don't think you'll find the clutch parts available by themselves. If you have a spare unit you could try swapping the clutches from one to the other. I haven't been into one in awhile so can't advise as to whether adding some lube to the squeaky one is a good idea or a disaster in the making, normally they run dry so the friction surfaces grab up on engagement. Knock the center nut off your spare unit and take off it's clutch, you can surmise whether putting a little lube into the one on your engine might help or whether you should just swap the clutch parts instead. A squeak in the clutch probably has about as much meaning as a squeaky brake, basically says nothing definitive about the actual state of wear of the friction surfaces and more about the effects air pollution and other ambient factors like humidity are having on the surfaces when they engage.

If you do remove the compressor, or any component within the fluid loop in this type of system, you do unfortunately have to evac and recharge the whole system. Older AC systems used to have service valves that let you isolate the compressor, older Mercedes were great that way, but I guess that got too expensive so it's all one enclosure, open any part of it and you have to do the whole pulldown/recharge dealy-o.

You ought to be able to get at least 35-40deg.F temp difference at the vents whatever refrigerant you're using, a really good R12 system will drop temp almost 50F. I guess what you're saying, though, is the net effect in the cabin your system is producing, not outlet temps? I don't get great cooling from my Redtek-charged system either because a couple years ago when I did it I didn't have a good vac pump so my pulldown wasn't the greatest, but with the overhead GL system the cooled air blows right at your head so it doesn't have to be that cool to make me happy. To redo it I would have to dump that fluid and do a long pulldown now that I have a better vac pump, but I don't feel like blowing the money when I'm satisfied with the performance as-is.
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[Californio]

That's good news. I'll start with the clutch and see where it goes. When I put the stethoscope on there, it sounded ominously like bearings rattling as well, but I'll swap clutches first. Nice having a pick and pull around so you can do these things--the compressor was $45 bucks or so, out of a 96 Jetta.

[tencentlife]

Just had another thought about this: the squeak could be a bit of belt slip when the clutch engages, since the application of torque is quite sudden, so check your belt condition and tension.
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Shop for unique Vanagon accessories at the Vanistan shop:
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Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[Californio]

Yes, that was the first thing I thought of, esp. as I was driving in dusty conditions. But hitting it with belt conditioner didn't make a difference, nor did changing out the idler pulley and tensioner.

However: now, after an hour or so of observing and listening, it looks like the squeak may be fan-related, not compressor. The compressor cycles on and off without making the sound, and what I thought was bearing noise sounds now more like ordinary compressor noise when the clutch kicks in. The squeak seems to happen when the fan goes on, esp. from zero and when it hasn't been run in a while--just like the front heater squeaks when they're just starting.

One of the things I like about working on these cars, and I say this without irony, is the way they test our powers of observation and logic. Time and again I find myself jumping right to the conclusion (here, "bad compressor") without verifying that my observations are correct and, usually, basing my thought process on emotion (oh no, worst case scenario!) rather than rigorous logic. Kind of a life lesson in a way.

Anyway, looks like a blower motor coming up...but will confirm before proceeding!

[Terry Kay]

<<About a week ago on a trip my AC started making a squeaking sound when it cycled on, and closer examination with stethoscope confirms that the sounds are coming from the pulley end of the compressor. I'm assuming this is a death knell for the compressor.>

Don't call the mortician yet.

What I want to know is where you were probing with the stethescope--
In the heater box, or back by the compressor?

Big distance between them to be verifying for sure that the compresor is taking the big nose dive--and then the sqeak is actually the heater fan motor.

Problem with this diagnostic --for sure--the blower motor would sqeal all of the time--not just when the AC clutch cycled.

I'd do some more sniffing here, prior to ripping the dash out of the Van or blowing off the charge in the AC system.

Maybe the stethescope's ear pieces are plugged a little--check that out first.
_________________
T.K.

[Californio]

Locating the noise is a big part of the problem. This is a Westy w/rear AC and I'm working by myself--hard to tell where in the back it's coming from.

I set the stethoscope probe on the top of the compressor and checked both ends. But I'm now thinking what I heard was just ordinary noise when the compressor cycled on. Sounded like bearings but I think that's just what they sound like.

Right now I'm leaning in the blower motor direction. It might be that the squeak occurred not because I turned the AC compressor on but because the fan went on at the same time. Running the AC with fan on lowest setting almost eliminates the noise, so I'm voting for the blower motor.

If I wanted to stick the stethoscope probe in there somewhere, is it possible to get it to the blower motor? That would for sure help.

[Terry Kay]

AC compressor's don't run silent--there is a bit of a growel to them--and if it was a sqeek, or a sqeal I'd for sure think it was a loose belt.

Crank the blower motor on without the Van running.
You'll be able to finger that bearing wail out of the evaportaor box pretty quick--without the hearing horn---
_________________
T.K.

[RicoS]

[Terry Kay]

Look for the Zulu's when you hear them beating on the Zebra skinned sheilds only--

I think with the engine cover closed and the blower motor on, one should be able to distinguish where the noise is coming from, especially right behind your head.

The blower on the way out & the AC compresor belt have two different distinct squeaks-- don't get nervous till you really know what's up.
_________________
T.K.

[tencentlife]

Easy to take the comp out of the picture by unplugging the clutch power, then listen to the fan.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[hecbom]

I had an identical problem last year and my solution to the problem was to replace the clutch. I found a good used unit for $45.00 at California Auto A/C. I also want to mention that I have been using Duracool in my unit for at least 3 years now and I can barely feel the compressor is on. My advice is to buy a clutch removal tool from “harbor freight” and don’t use a 3 jaw puller or you will definitely ruin the clutch.