Write-Up: AC Compressor & Clutch Replacement

Compressor replacement #1:
https://rivperformance.editboard.com/t6120p45-write-up-ac-compressor-clutch-replacement#116273

Compressor replacement #2:
https://rivperformance.editboard.com/t6120p75-write-up-ac-compressor-clutch-replacement#131806



My A/C compressor clutch seems to be going out on me. If the air conditioning is on there is very little noise coming from the engine compartment, but as soon as I shut the air conditioning off you can hear the compressor shut off and then a very loud piercing almost metallic whirring sound. Upon closer inspection you can actually see the compressor pulley wobble slightly. i brought the car to my mechanic who builds engines, and can diagnose just about any engine noise just by looking, and he said it was the ac compressor clutch. Is it possible to replace just the clutch or are these compressors the type that need completely replacing? Anyone ever have this issue?

The clutch is replaceable separately.
I had mine replaced at the dealer a couple of years ago.

Rickw wrote:

The clutch is replaceable separately.
I had mine replaced at the dealer a couple of years ago.

Glad to hear that. Any idea what the cost was? I was going to drive it until it stopped functioning, but I'm getting strange looks at the stop light now it's so loud unless I have the AC on. It sounds like I have a cat under the hood that had it's tail stepped on.

I'm curious about this too. Pretty sure mine is done.

i don't know how much it cost to replace the clutch assembly.
I had an extended warranty at the time and it was a covered item.
They replaced that and the expansion valve, filter and flushed and filled the system along with other work i was having them do.
You'll have to get a quote from any shop capable of doing AC repairs. I would have it done sooner rather than later.
Right now the clutch is making metal shavings and sticking to the magnet in the clutch assembly. Things only get more expensive as time goes on.
In my case they were still able to remove just the clutch and replace it, but I've been told if you wait till it completely fries then it may get seized to the shaft and your looking at a whole new compressor. Not cheap.

Well I ordered a new clutch assembly from Autozone for 93.99. They were the only parts store that even carried it. Every other place I went the only thing they offered was the whole compressor and clutch assembly. Which was $300 for the cheap model.

Now does anything else have to be done to the system when the clutch is changed besides refill it?

Removing the clutch does not require removing any freon. It is totally separate from the pump part of the compressor. All you need is the proper puller as far as I know.

Rickw wrote:

Removing the clutch does not require removing any freon. It is totally separate from the pump part of the compressor. All you need is the proper puller as far as I know.

D'oh that's right. Nevermind.

So the clutch went out on me again. 3 month warranty of course so I'm stuck buying another one. Doesn't make any noise or anything, it just will not engage. You can hear it trying and the RPMs fluctuate, but it will not engage. I got pissed off at it, and took a screw driver out and starting to bang on it (this is what I do when nothing else works), well long story short I can now engage the AC clutch by taking a long screw driver, quickly inserting it between the clutch and the pulley and twisting it. That causes the clutch to engage and I have AC. I refuse to get out, open the hood and use a screw driver to turn my AC on, so I'm replacing it again. Wish there was a higher quality clutch assembly for around the same price, but if I was to get the AC Delco clutch assembly, it'd be as much as the compressor and clutch combo. I don't want to replace the compressor and screw with the coolant already in the system and replacing the evaporator and whatnot too.

Very frustrating, hopefully this next one lasts.

Ended up being the AC Compressor. Got that replaced and the money from the clutch refunded and I'm all set now. That is until the next thing...

Lately I have been having a metallic grinding noise coming from the engine bay and I have narrowed it down to the A/C compressor. Usually, whenever the A/C is turned off the noise persists, and upon engaging the A/C from inside the car the noise ceases (My A/C also blows nice warm air ). Anyway, I have been reading around and found other 3800 owners with the same noise claiming that the A/C Compressor Clutch or Pulley Bearing is worn out. My question is, is it worth (and feasible) trying to repair the clutch on my OEM compressor? Does it require opening the refrigerant system, at which point it would be better just to put a new compressor on? I apologize in advance for any errors in this post as I am still not well versed in the world of A/C.

The clutch assembly is replaceable without going into the A/C system.
It requires a special puller.

If you have no A/C now, I would be sure it wasn't just the clutch. It could also be a problem with the compressor. If that's the case then you will have wasted your money on a clutch, unless you can find a rebuilt compressor without a clutch.

Rickw wrote:

The clutch assembly is replaceable without going into the A/C system.
It requires a special puller.

If you have no A/C now, I would be sure it wasn't just the clutch. It could also be a problem with the compressor. If that's the case then you will have wasted your money on a clutch, unless you can find a rebuilt compressor without a clutch.

Well the air blowing out isn't necessarily hot, its more lukewarm. Could this be a sign that the clutch is not fully engaging?

It would take some hands on diagnosis to tell what is going on with your A/C system.
Sorry.

Rickw wrote:

It would take some hands on diagnosis to tell what is going on with your A/C system.
Sorry.

I'm not looking for a clearcut solution to my issue, rather just trying to understand the system and how it works. So is it plausible to think that a failing clutch wouldn't engage and activate the compressor properly, or am i way off base?

L67 wrote:

Rickw wrote:

The clutch assembly is replaceable without going into the A/C system.
It requires a special puller.

If you have no A/C now, I would be sure it wasn't just the clutch. It could also be a problem with the compressor. If that's the case then you will have wasted your money on a clutch, unless you can find a rebuilt compressor without a clutch.

Well the air blowing out isn't necessarily hot, its more lukewarm. Could this be a sign that the clutch is not fully engaging?

Generally the clutch either engages or it doesn't, no in between.
It is an electric clutch.
Watch under the hood whith a flashlight while someone else turns on the climate control. If you see the clutch engage and start turning then that answers that question, almost. Look for metal shaving stuck to the clutch, there is a strong magnet involved in that clutch and if it has metal shavings all around it, it is a sign that the compressor is operating with too much resistance possibly, or the clutch itself has just gone bad. There are a lot maybe's and if's when it comes to properly diagnosing the A/C system.
The next question is: does your system have a leak and has it leaked some freon out giving you something less than cold air.
This is where a set of gauges will come in to play, to measure the High and Low pressure sides of the system.
I do not know what they should be off the top of my head. The FSM may tell.
Or you can buy a can of freon, R134A that comes with the installation hose, install a can of that for about $10.00 and see if you get colder air out of the dash.
If you are, then you need to pay someone to find and fix the leak(s).
Maybe one of resident mechanics can chime in and offer some better diagnostic advise.
Good Luck

L67 wrote:

Lately I have been having a metallic grinding noise coming from the engine bay and I have narrowed it down to the A/C compressor. Usually, whenever the A/C is turned off the noise persists, and upon engaging the A/C from inside the car the noise ceases

What you are describing is a classic idler bearing problem. When the pump is stationary and the pulley/hub is freewheeling, you're hearing the worn-out bearing in the hub. When you engage the clutch, the hub and compressor shaft turn as one, so the idler bearing is no longer turning and no longer making noise.

Unfortunately, I have no idea how deep one must go to fix this on a V-5 compressor, and the location makes it very difficult to work on... In the book, it sounds like the hub & clutch come off together, while on the one pump I ever worked on, the old A-6, only the clutch came off with the puller. I strongly suspect that this is a job for an established A/C shop.

Thanks for all of your responses guys, I figured the A/C was probably too much for the Sunday afternoon mechanic anyway

A/C repairs are either $100 or $1000. Good luck.

Will a compressor from another 3800 powered car (L67 or L36) fit a Riviera?

Yes, AC compressors from the following are interchangeable:

BUICK LESABRE 1999
BUICK LESABRE CUSTOM (1996 - 1998)
BUICK LESABRE LIMITED (1996 - 1998)
BUICK PARK AVENUE 1996
BUICK PARK AVENUE ULTRA 1996
BUICK RIVIERA (1996 - 1999)
OLDSMOBILE 88 1999
OLDSMOBILE 88 ROYALE (1996 - 1998)
OLDSMOBILE 88 ROYALE LS (1996 - 1998)
OLDSMOBILE 98 REGENCY ELITE 1996
OLDSMOBILE LSS (1996 - 1999)
OLDSMOBILE REGENCY (1997 - 1998)
PONTIAC BONNEVILLE 1999
PONTIAC BONNEVILLE SE (1996 - 1998)
PONTIAC BONNEVILLE SSE (1996 - 1998)

Thank you sir.

For the record here are some (probably) useful posts on AC clutches:

1) a clutch repair (information only - diff type of compressor)

http://www.bernardembden.com/xjs/comclutch/index.htm

2) a chart of clutch problems and causes with commentary

http://www.ryderfleetproducts.com/cgi-bin/ryderfp/technicalbulletins/acClutchfail.jsp

3) Other comments (same type compressor as ours)

http://flashoffroad.com/Maintenance/hvac/airconditioning/clutchPullyService.htm

Albertj

I finally found the leak in my AC system, its the seals on the compressor. Rather than try to repair this one with its failing clutch (can the seals even be replaced?), I bought a brand new Delphi replacement from rockauto. I plan on installing it myself, but having a shop charge the system. I also bought a new orifice tube and accumulator. The instructions mention I need to add oil to the new compressor, and to measure how much I get out of my old one. How do I get the old oil out, and put the new oil in? I see what might be a plug on the housing of the new compressor, do I pull that out, or does it pour out through the refrigerant fittings?

moldymac wrote:

I finally found the leak in my AC system, its the seals on the compressor. Rather than try to repair this one with its failing clutch (can the seals even be replaced?), I bought a brand new Delphi replacement from rockauto. I plan on installing it myself, but having a shop charge the system. I also bought a new orifice tube and accumulator. The instructions mention I need to add oil to the new compressor, and to measure how much I get out of my old one. How do I get the old oil out, and put the new oil in? I see what might be a plug on the housing of the new compressor, do I pull that out, or does it pour out through the refrigerant fittings?

IIRC it pours out thru refrigerant fittings.

As it turns out I have my FSM set tonight. The PAG oil charges for the HVAC system on the 1998 Riv, according to the FSM:

COMPRESSOR = 240 mL = 9 fl. oz
EVAPORATOR = 90 mL = 3 fl. oz
CONDENSER = 30 mL = 1 fl. oz
ACCUMULATOR = 105 mL = 3.5 fl. oz
REFRIGERANT CAPACITY = 0.91 Kg = 2.0 lbs.

SO - you ought to get about a cup and a tablespoon-ish of oil out of the compressor. Watch out for the possibility that the previous owner added refrigerant with oil to the system. If I was you I'd use the chart from the FSM. It says that when you replace the named component (Condenser for instance) you need to pour that amount of PAG oil into that component (1 oz).

Albertj