I have a 1999 F250 with the 6.8l. Recently (right after I got done with the hellacious plug change...) I started hearing this loud rattling noise occasionally. I traced it to the pulley on the AC compressor. I'm not sure if it is just a bad bearing or if the entire clutch needs replaced. When I turn on AC the clutch does lock in and out properly. At idle with the pump off it makes a faint grinding noise, however when the clutch engages it becomes very loud. Loud enough to be heard clearly over a Magnaflow exhaust with no cat.

I'm wondering if I should replace the bearing or the entire clutch/pulley assembly and more importantly: how urgent is it that I fix this? I'm traveling make to college this week and don't know if I'll be running the risk of that pulley popping off mid trip and becoming SOL.

Thanks in advanced, sorry if I forget something important- feel free to call me an idiot.

 

Also wondering if anyone knows the belt length to simply bypass the compressor as a temporary solution until I have time to fix it.

 

Remove the serpentine belt and check both the pulley and the clutch plate.

If it's just the plate that is noisy, you can easily remove it (just don't loose the bolt and any shims behind the plate) to eliminate the noise. If it's the pulley itself (bad bearings), the pulley will need replacement.

 

Well here's what I wound up doing in case anyone else finds a similar problem one day:

Turned key position to on and turned on "Max AC" to lock in clutch
Removed front bolt from compressor clutch assembly.
Removed serpentine belt (if you don't I the tool, I just take a 1/2" drive ratchet to the tensioner and use the tire iron under the hood on the end of the ratchet for leverage)
Make sure to turn the AC back off to release the magnet (I tried for ten minutes before I realized what was stopping me so maybe I'm just ignorant)
Slide front plate off of assembly. It came off easily after I turned off the magnet. There is a shim behind it so watch for that.
I then greased the inside of the assembly from both the now revieled front side as well as from the back.
Reassemble

The rattling is completely gone for now. Hopefully this temporary fix will hold awhile. I wonder if the bearing had just "dried out." I'll probably replace the bearing should the problem return since the clutch itself seems fully functional.

On a side note, being new to this forum, I wonder why it is displaying my real name on these posts. I've looked around the user control panel but can't find any option to set a screen name like everyone else apparently has.

 

You likely entered your real name when the forum software asked for a screen name. Can't change it now.

Hopefully, you didn't get grease on the contact surfaces of the clutch and pulley..

 

Mine sounded like that, then it started squealing one day once I started it, then snap! There goes the belt! Pulley was completely seized, bearings all in a bunch when I dropped the compressor out....

Goodluck

 

Mine has been rattling for the past 1500 miles, but since it's winter... I'm going to hold off and save money for a new unit.
Annoying sound, but harmless in my case.

 

Don't bet on it being harmless.

On my old 97, I did that and ended up on the back of the AAA flatbed when the pulley bearing seized and locked up the whole engine via the belt.

 

just replace the clutch assembly.. not expensive. just did it on our 03 f350.. cost about $60 from autozone.. took a whole 30 min to do. but if that bearing goes out or locks up, it can burn up the belt or fry the compressor, over heating it , melting the seals. loosing the freon and costing 4x the amount to fix. i have had this happen before. $60 clutch vs $180 compressor, $100 AC fill, $25 belt

 

Just had the compressor seize on my 6.8L Excursion. Didn't realize it came out from business meeting and truck wouldn't start tension on belt caused computer to shut down starting. Took belt off and truck started right up but now I get to do full A/C job.Wish you would have had a belt size solution so I could have limped home!

 

The computer did't shut down the starting attempt. It's purely the mechanical binding.

 

Dorman makes a pulley that takes the place of the compressor. Not as good as a shorter belt, but cheaper than a compressor for a temporary fix for a stranded truck. Think it was around $28.