328 AC Compressorclutch replacement

Just fully charged my A/C in my 328 and I am getting a loud ticking noise when switched on.It sounds like the clutch making the noise.
I would assume this is not a bearing that you could replace in the clutch either?

Does anyone know if you can replace the clutch with a standard York unit and use the Ferrari pully or is it a complete unit?

It could be the compressor also, from what I understand they are no longer available new and only rebuilt.

My other alternative is to switch to a Sanden but it looks like a lot of work to fab a brackett and get the lines to fit etc., so I'd rather keep it simple and fix the clutch or replace with another complete unit, I avoid driving it in the hot daytime anyway but it still does keep the car relatively cool with the stock unit.

Hi Jeff,

I don't know if there is a proper "replacement" clutch other than the original unit. They aren't terribly expensive at $200-esque new. However, if you could source it, I think there's a bearing held in place with snap rings in there (it's been a while since mine was apart). New York compressors - without lower metric threads though - are still available from NAPA for about $350-400 or you might want to try these people http://www.rparts.com/ seem to have good prices if compressors are "new".

Best,
Carl

Thanks Carl,

I'll check into it further.

Great tech article BTW on 328 A/C.

Regards

It's possible that one of the pressure switches is cutting off the clutch, so you are hearing the clutch chatter as it engages/disengages. It does make a nice metallic clanking noise.

If the problem was the bearing, it would make noise when the clutch was disengaged. When the clutch engages, the bearing is not relevant.

Sounds like a system pressure check is needed.

Another thing to try is removing the wire to the clutch and jumping it to 12V to make sure the clutch works. See if the click noise is what you are hearing. However, I wouldn't do it with the car running...if there is a pressure problem, you would be overriding the high pressure cutoff switch and you could blow something apart.

How was the system charged?

Hi Phil,

The clicking noise has been present for awhile, when I just had my cambelts changed they removed the compressor and recharged the system, the noise is a consistent clicking not the single click as the compressor cycles on an off.

The system only had .9oz of freon but it still blew cold. When they evacuated and recharged the system they put in the 2.2lbs of freon and the noise is louder now, the tech thought it could be the clutch but you are right also it could be the compressor going out as well.

It only makes the noise when the compressor is switched on, otherwise its fine.

Try squirting a little silicone spray or penetrating fluid on the belt and seeing if the noise goes away.

What happens, so the theory goes, is the belt kinda wedges in the pulley groove and the noise is it popping back out again. It's usually worse when it's cold, and when really cold doesn't matter if the a/c is on or off, it makes noise. Turning on the a/c will load the belt a bit and cause it to pull harder into the groove.

If that's the problem, you either ignore it or change the belt. Was the belt replaced when the tbelts done?

You can also see if the electronics are toggling the clutch by checking the voltage at the clutch wire connector to see if it's fluctuating.

I didn't mean to say it could be the compressor itself. There are bearings and valves inside the thing which could make noise, I guess, but assuming the oil didn't leak out of it, it doesn't seem likely (that statement will probably insure that it is the compressor failing :-))

btw, run your hand along the hoses where they loop up over the gas tank. Quite often, they rub against the frame or top of the tank and a divot wears into the rubber. When the divot gets deep enough, the hose blows. If you feel the divot, wrap that part of the hose with another piece of hose or that dense foam pipe insulation stuff from a hardware store.

Thanks Phil,

Yes its a new a/c belt.

The noise sounds more mechanical, like a knocking sound,not so much a rubbing noise or vibration, its clearly the compressor or clutch, its possible one of the pistons is going out in the compressor or the clutch failing.

The a/c blows cold now but does not blow as cool at idle as I remembered when I last charged it 3 years ago, it was this way about a year later after I charged it which I assumed some of the freon had leaked out which it had.

It's my understanding that the Sanden unit used on Euro cars is much better than the York. The conversion to Sanden has been done several times and all report positive results. I fellow named Steve Carr at Carr Auto Parts in Houston (713-690-1800) has been mentioned as being an expert at this and providing complete kits.

hi jeff,

When the belt is making the noise, it's a ticking sound.

Assuming the woodruff key is installed in the clutch shaft, the only thing the clutch could do is rapidly engage/disengage due to electrical/pressure problem, or the clutch could slip.

If it's slipping, the pulley would usually get very hot, melting the belt, bearing seals, and/or damaging stuff in the compressor.

Sounds like you are going to have to pull things apart. You can remove the clutch without disconnecting the compressor hoses. The magic tool needed is a 5/8" bolt from the hardware store (11 threads/inch) and an impact wrench. After unbolting the compressor so you can spin it around to get to the clutch, use the impact wrench or carl's method to remove the shaft bolt. Then use the 5/8" bolt in the pulley hole , which is threaded. Use the impact wrench to screw the bolt in, and the pulley slides right off. You could probably hold the pulley with a strap wrench or the belt and use a wrench to drive the bolt, but that's lots more work.

Other tests you can do without taking anything apart is measure the voltage at the clutch wire, which should be 12V+ when the a/c is on, and measure the resistance of the clutch winding, which should be around 300 ohms.

If you want to try replacing the clutch and not the compressor, I have a spare clutch you can borrow. However, I can't think of a way the clutch would cause the symptoms assuming it's staying engaged.