james1

I have a squeak in the front of my engine. I removed the belt and hand checked the water pump, alternator, A/C compressor, and fan; all seemed fine. I installed a new tensioner to no avail. The squeak is somewhat intermittent. I don't think it's the A/C compressor as it makes no difference if the A/C is on or off. The alternator is charging well.

So would a failing clutch on the radiator fan cause a squeak? What happens if it fails completely? (I'm currently travelling several hundred miles from home.)

TIA.

maybe368

I'm not sure about the clutch squeaking, but don't forget to check the big fan bearing...Mark

delsilver

I had a fan clutch fail I a Mercedes I used to own, squeaked intermittently, drove me nuts trying to find the squeak.
Have you changed the belt, that was the problem I had in my 93.
Del

james1

Thanks for the prompt replies.

How do I check this? I couldn't make the fan squeak spinning it by hand (which I realize is hardly a real-world test).



The belt is not ancient and seems to be in great shape. The new automatic belt tensioner I installed was so tight I cannot imagine the belt is now slipping, but a new belt is certainly easy enough to warrant trying.



Thanks; that's good to know.

j_martin

If the belt or the pulleys are worn so the belt bottoms out, it'll squeak. Also, very little oil or antifreeze on the belt will make it squeak.

The sides of the v grooves in the pulleys should be a straight line to the bottom. If there's even a little step in the v, the belt rides on the step with little traction and squeaks. This is more prominent in V belts, but the multi-v's can also suffer the fate. The angle of the sides of the grooves increases the traction (pressure) by a huge percentage, like 300 - 400%. If the fit because of wear allows the belt to bottom out, the traction is reduced by that percentage.

maybe368

"How do I check this? I couldn't make the fan squeak spinning it by hand (which I realize is hardly a real-world test)."

It is a massive, tough bearing. I imagine that if it turns smoothly, without any gritty feeling, that it is probably good. Try removing the belt and starting the engine, if the sound goes away at least you know it is something driven by the belt. I suppose that this doesn't really eliminate anything, ...Mark

james1

Thanks for the replies.

I finally heard a change in the pitch of the squeal, depending on whether the A/C was on or off. I was in Nashville and needed to make the 250 miles home to Atlanta. So I lifted a page from Bearkiller's playbook -- I purchased a belt for a non-A/C truck.

Dodge was courteous enough to paste a belt routing diagram on the underside of the hood that includes engines both with and without A/C. I needed about 10 minutes to remove the old belt and install the new shorter belt, which took the A/C condenser out of the equation. Voila, no more squeak; and I made it home to Atlanta without incident.

Unfortunately, now I must deal with getting the A/C condenser repaired before summer hits with a vengance here in the Deep South .

Again, thanks to all.

maybe368

Not too bad a job, see here ...Mark

james1

Thanks Mark. That's a great thread. I didn't have the same problems as you with the tensioner. My new automatic belt tensioner (Dayco brand) came with a 1/2" square hole; my 1/2" drive Craftsman "power bar" slipped right past the radiator fan and into the tensioner with no problem whatsoever.

I profess complete ignorance regarding A/C systems. My A/C is currently blowing nice and cold, although I suspect the squeak means something on the compressor will fail shortly.

I assume there is no way to remove the compressor from the truck without losing all the R-12 Freon out of my A/C system? The squeak from the front of the compressor is likely a clutch that turns the compressor on and off -- is this part serviceable or is a whole new compressor in order? (In an ideal world I would simply repair the compressor and continue using R-12 in the system.)

I apologize in advance for stupid questions...

maybe368

You're right that it is probably the clutch bearing and there is no way to remove it without blowing the charge. My brand new clutch squeaks so I decided to buy a non-ac belt and let her go until she lets go. They can go many miles without failing, that is my hope...Mark

rrgrassi

Yes, you can remove the entire a/c clutch assembly from a compressor. The pulley bearing can fail allowing the pulley to rub on the clutch plate, and become out of line, allowing the belt to squeak.

maybe368

That is true, but, at least on my 90, there is no way to access the clutch without blowing the charge...Mark

j_martin

Before you get all carried away, the AC compressor puts a big load on the belt, and if it's prone to, that's when it'll squeak. Try a new belt before you spend a lot of time and money on it. Also look at both the crankshaft pulley and the AC pulley for signs of wear as I stated previously.

Compressor squeeks usually occur when not turning, and are in the idling bearing in the pulley assembly. When the clutch is engaged, that bearing is bypassed (locked up so to speak) and the only noise would be from the compressor itself. It would be unusual for it to do that very long without total failure.

rrgrassi

I think my '90 may be the same way. It's a dumb set up if you can't remove the clutch and pulley without losing the freon.

You can buy one with out the clutch. It looks to be a C-171. I do know know if a Sanden was used in 1990 or not. The link below is for a 4-Siezing

http://www.autopartswarehouse.com/sk...r/FS57038.html

It looks like you can remove the clutch without losing the charge.

maybe368

I never meant that the clutch couldn't be removed without blowing the charge, only that the problem is there is no access to the clutch and the only way to get at it is to lower the compressor, which requires blowing the charge...Mark