Belt Chirp Driving Me Bonkers!

[Scottn59c]

I've had an ongoing saga with either belt or pulley noise going on ever since I had my mechanic install a new A/C compressor.

The EV started making the noise the very day they installed it. Took it back in and they told me they thought it was the idler pulley. I replaced it - no help. Next, they suggested changing the serpentine belt. Did that, no help. A second mechanic cleaned and lubricated the pulleys and suggested changing the waterpump. Changed the waterpump, still have the noise. All of these swaps made the noise go away for minutes, or even five or ten miles, but it comes back.

Yesterday, I poked around and spun all the pulleys. Everything looks good and I see no obvious problems. My suspicion is the A/C unit itself. Although it's working and the clutch looks solid and the pulley spins freely, I keep thinking, what the hell else could it be? The van was running noiselessly until the installation of the A/C. The shop says they did it right, so is it a faulty compressor? Kinda doubt that. Maybe the belt chirp I'm hearing is a pulley misalignment problem. squirting water onto the serpentine belt eases the noise momentarily. Perhaps the shop didn't get all the pulleys aligned or under or overtorqued that A/C pulley?

Yesterday I flipped the double sided serpentine belt around and had the van running without the noise all day - drove around for 10 miles or so. Was ready to declare victory, but then this morning, I started her up again and the noise is back. Now why would inverting the belt help, but only temporarily? I can't figure it out! Please help!
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Farfignewton!

[Abscate]

Tough one.

The common theme I see there is heat. After a few minutes, if a bearing is warming up, it will start to chirp.

Take a piece of Tygon (tm) hose, about 1/2 diameter, and make a stethoscope. Use it to nail down the location of the chirp +- 1 cm.

I bet you have a bearing in the idler, PS, or AC that is warming up and talking to you.

When the chirp returns, if you flip the belt back, I bet it won't go away.
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.ssS!

[93EV]

Take a look at this YouTube video by ChrisFix. It helped me diagnose what turned out to be a bad belt on one of my cars.

https://www.youtube.com/watch?v=AEUe6uKxTv8

If it is the belt, you may want to look into the Goodyear Gatorback belts. Some people like them, some don't. I used one on my car that squeeked with an OEM belt and it eliminated the noise for me completely so I was happy with it.

Good luck.

[Scottn59c]

Thanks Guys,

I took Abscate's advice and made a ad-hoc stethoscope to listen in and isolate the noise. It's coming from the A/C pulley.

I suspect pulley misalignment and am taking it into the shop tomorrow. If it is a misalignment, the shop should be on the hook for righting the ship, given that I paid them to install the A/C.

1/29 - update

The shop informed me that they believe the A/C compressor is defective. Mechanic felt there might be an internal component that is damaged or missing. Buyautoparts is sending me a new one and I'm hoping for better luck with this one.
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Farfignewton!

[Scottn59c]

Dammit, am I in a pickle now...

I had Buyautoparts (from whom I bought the A/C compressor kit) send me a second one, for which I had to put down a deposit. It arrived and my mechanic took the van into the shop to install the new one.

The mechanic called me an hour later to say that the new compressor doesn't fit properly and has the exact same problem as the other one - evidently, there's a gap in how it lines up that is creating a pulley misalignment problem. While the AC system works, I'm still left with a misalignment that is causing a chirping, but worse, that could wear the serpentine belt out or incapacitate the vehicle at any given time. The mechanic tells me he's positive the shop installed it correctly, and that he'll give me pictures he took that show the gap on Monday.

Called BAP and they assured me that the part I ordered is an aftermarket one, but the proper replacement, given the OEM part number. They tell me they've sold 14 of these same AC compressors in the last month and I'm the only one to complain. They are pointing the finger back at my mechanic.

I have no idea who's telling the truth and who's full of crap. I'll post the mechanic's pictures when I get them. I kind of suspect the mechanic hasn't properly installed the thing - how could BAP sell 14 units that don't fit and only have one complaint?

What might the mechanic be missing? The A/C functions, so it's not a clutch gap - it's a pulley gap (I think? Correct me if this sounds like a spacer issue) Mechanic says there's only three main bolts - not a lot of possibilities to screw it up.

If anyone's installed an A/C compressor himself, please weigh in. Abscate, if you read this, you've been a helpful ally so far. Any ideas?
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Farfignewton!

[Abscate]

What year EV are we on Scott?

Ive got that warm fuzzy feeling with your user name that you share with me ownership of the best T4 - the 2002

Ill be happy to make some measurements on mine - I replaced mine on warranty a long time ago with an OEM replacement
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.ssS!

[Scottn59c]

It's a 2002, indeed. It's a great van, but not without its warts!

I'll get the mechanic's pictures up on Monday to see if they tell anything. FWIW, the compressor I bought is an aftermarket and not the OEM (though, as I said, 14 other people this month were evidently ok with it). Buyautoparts says they're sure this is the right compressor, and obviously it's very close since it's functional, but not fully in alignment with everything else in the the drive belt.

I'm a bit SOL because the mechanic doesn't have to warranty a part I brought to him. I'd think, though, that he would need to warranty his work if he's installed it incorrectly. I may have to get a second opinion to find that out?
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Farfignewton!

[Zeitgeist 13]

looking forward to seeing those pics. Most serpentine belt configurations require tight tolerances for fitment of the appliances, so it's not surprising that an aftermarket unit has issues. It's possible that the compressor wasn't "clocked" correctly when it was assembled. Just speculating here, until the pics arrive.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Abscate]

[Scottn59c]

Pictures from mechanic attached. It appears that the aftermarket pulley is a bit shorter than the OEM one, yes?

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Farfignewton!

[Abscate]

Just remembered I have the OEM AC in my shop from that job

if you PM me coordinates Ill send pix (I'm at work and can't up/download easily)

Good news is you can just shim it out, right?


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.ssS!

[Zeitgeist 13]

Did he try swapping the pulleys?
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Scottn59c]

Zeitgeist 13, the mechanic installed the new compressor (that I bought and brought to him) and recycled the old one. It took awhile before we realized we had a pulley misalignment problem. The OEM one he used in the picture, he ordered to use as a basis for comparison, but not installation. He's not going to warranty a part I brought to him (understandably). Long story short: can't swap the pulleys.

Abscate, the shop said they couldn't create a shim, but didn't give me a great explanation about it. Don't worry about those measurements, but thanks for your helpful offer.

What I did was email my pics to buyautoparts and they agreed to accept my return and allow me to exchange (and pay the difference) to get the OEM compressor. That should hopefully solve things for me.

The lesson I learned? Don't buy aftermarket junk - get the OEM and you'll save a lot of headache!
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Farfignewton!

[Zeitgeist 13]

Sheesh, what a hassle.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Abscate]

OEM is best, but Im sure you could pull that clutch, shim the clutch out the 3-5mm or so. That kind of stuff is beyond most mechanics nowadays, unfortunately

You've certainly reminded me to pull off my AC clutch for spare parts though - thats about a $200 part right there.

One other thought. You have to reference the pulley to the mount face, not the bolt head to compare. Make That the measurement if you can. You might be able to grind 3 mm off the mount face and position the aftermarket pulley correctly that way.

Archived here for the next guy to hit this issue


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.ssS!

[Stripped66]

Your mechanic needs to take measurements from the mounting surface to the pulley in order to compare their offsets. One pic locates the tape measure on the face of the compressor cover, the other pic locates it on the bolt. The pics you posted could have any degree of dimensional variance that does not affect the actual alignment of the pulley whatsoever because no reference has been made to the actual mounting surface.

I'm not refuting that a misalignment isn't there, but all the pictures demonstrate is that your mechanic doesn't understand how the A/C compressor is mounted, or how the relationship of the mounts to the pulley determines its offset. Unfortunately, you don't either. So, that makes finding the solution all that much more difficult when neither of you know what the actual misalignment is.
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[Abscate]

I think my post was kinder and gentler, but you are right about the measurement.
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.ssS!

[Scottn59c]

You're both probably right (though yes, Abscate was much softer in his delivery). Perhaps a shim could be made, but the mechanic doesn't have the know-how or the desire to bother. It's probably outside of my ability too. If the OEM replacement fits and the shop picks up the labor, I'm only out an extra $100 or so. The frustration of trying to adapt the aftermarket compressor to fit isn't worth more than that to me.

I can't tell if the measurement that on the aftermarket compressor is taken from just behind the nut or on top of it, but it's hard to imagine that the tech would be clueless/careless enough to measure each one differently. The pictures may not prove a difference in measurement, but there is definitely a pulley alignment problem.

If the mechanic can't make the OEM replacement fit, then he'll have some explaining to do. Otherwise, hopefully this gets resolved without any further issue.
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Farfignewton!

[Stripped66]

[Scottn59c]

And the lunacy continues...

I just picked it up from the shop where the owner and I vented our frustrations at each other. After I ordered and brought in THE EXACT same OEM compressor that he used in the pictures I posted two days ago, he calls me this afternoon to tell me that his tech got the compressor on, and it fits properly, but he claims that this unit has a problem holding refrigerant. He tells me his tech watched in horror as his pressure gauge surged over 300 PSI and had to abort before it blew the pump. Claims they tried twice and had the same results.

He's telling me the THIRD pump I've brought to him is defective. He also muttered something about the compressor not having any oil in it when it arrived, and that he had to put some in, and that maybe this is related.

In the end, he told me that he's done trying to get it right and that I can take it to a VW specialist. He did concede that if a VW specialist finds his tech screwed up that he would refund me the labor costs.

So...

I'm out of money and frustrated, as you might imagine. What could cause the PSI to surge? Any thoughts or ideas or experience you guys can help with? What are the odds that three compressors are problematic? Pretty slim, right?
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Farfignewton!