serpentine belt squeals over AC pulley with engine running

ptsal

Member
Joined
Dec 20, 2007
Location
Wisconsin
TDI
98 Jetta TDI
I have a 1998 jetta tdi. 255K All stock parts, most are original to the car.

The latest problem is a stuck AC pulley under load. It spins freely with the belt off but doesn't move with the belt on and engine running causing the belt to squeal. Tensioner and pulley seem ok.

Any ideas on an emergency fix and/or permanent fix?


Thanks for any help.
 

turbodieseldyke

Veteran Member
Joined
Jun 6, 2010
Location
Free Mustache Rides
TDI
98 jetta
Hopefully you can just unplug the wire to the AC.

If that doesn't help, then depending on how far you need to drive, an emergency fix could be to remove the belt, and run without the alternator for a few miles, and charge your battery offline between trips.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Um, are you trying to run the AC? The clutch should not be engaging, and the pulley should free spin very easily. Not sure why yours is easy to spin with the belt off, and that changes with the belt on.

I used to see compressor delete kits for sale. It was basically a bracket and an idler pulley. They were about $25.

-Todd
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
If its doing this with the AC OFF, a few things can trigger it, easiest of all is to UNPLUG the AC. Look under the alternator, on the top of the AC there is a connection for 2 wires, unplug it! If that does not fix the issue, your clutch is TOAST and you will need replacement in some regard or its not going very far.
 

iluvmydiesels

Veteran Member
Joined
Nov 21, 2015
Location
phila area
TDI
AHU
a couple of things. if the pulley is freely turning with the belt off, it should turn with the belt on, A/C should be off in this situation, the outer portion of the pulley will turn, the 'inner' is the compressor/clutch, that should not be turning. if the 'outer' pulley is turning (belt on here) and you cannt tell for sure, and you have a squeal, it could be from alternator. it could be the battery, charge, or bad, alternator, (alt) pulley, or belt. <- if the tensioner is ok.
check battery voltage, alt charge volt, and +/- connections, grounds, even alt wire loom connection.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
sounds like you're losing the AC compressor clutch bearings but since I haven't seen a vid of it I can't say for sure. If the belt is squealing then the pulley must be dragging a decent amount.

This might be where you pull the serpentine belt and see whether the compressor pulley is moving freely. Also check to make sure alternator pulley is free too.

Steve
 

ptsal

Member
Joined
Dec 20, 2007
Location
Wisconsin
TDI
98 Jetta TDI
The squeal is definitely from the clutch not spinning with the engine on, alternator pulley is ok. Squeal happens with the engine running and AC off. Thanks for the ideas. I'll disconnect the electrical to it and see if it frees the clutch. I'll let you know what happens.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
The squeal is definitely from the clutch not spinning with the engine on, alternator pulley is ok. Squeal happens with the engine running and AC off. Thanks for the ideas. I'll disconnect the electrical to it and see if it frees the clutch. I'll let you know what happens.
it wont, but it should be unplugged.
So the real question is, does it operate fine with the AC on? Just leave the AC on!, its only winter lol!
 

iluvmydiesels

Veteran Member
Joined
Nov 21, 2015
Location
phila area
TDI
AHU
your explanation is slightly off ptsal. the clutch not spinning isnt technically correct. with the A/C off the clutch is released, the pulley is like an idler, the outside spins, freely, so the belt can turn other accessories and they can 'operate'.
if its the case, the solution is usually as simple as a new compressor. what it sounds like is your compressor and/or pulley is seized. if the pulley doesnt spin with A/C off you wont be able to get alternator juice with out the pulley working properly.
 

ptsal

Member
Joined
Dec 20, 2007
Location
Wisconsin
TDI
98 Jetta TDI
well, it seems to have fixed itself when the weather warmed up. ordered a new compressor and will install when warmer weather prevails.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
im fairly sure you can just swap out the pulley
if the pump really is fubar, make sure you have a certified tech do your AC or do it PROPERLY yourself, either way dont cheep out on AC parts. also dont by aftermarket crap, its all crap, go OEM or your going to be replacing a compressor very soon again.
 
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