Compressor/clutch noise - cause for concern?

[laneo9417]

Hi all - I heard a grinding/cranking noise this morning while driving to work when I switched from the floor to the floor and front defroster setting on my Ex. I heard the usual audible click of the compressor but then it made the grinding noise for a quick second or two before going away. The truck ran fine before, during, and after this happened and did not make the noise when I later switched between the floor and floor/defroster setting. I've done some quick research on this topic this morning and I'm lead to believe it could be a bearing in the compressor or the clutch? I apologize as I'm not too familiar with the setup or how a compressor/clutch/AC system works. I would like to note that it was very foggy and damp out this morning so I'm not sure if the excess moisture had something to do with this, or the fact that I had not driven the truck in the two days prior. I just want to know if this is a warning sign or just a flukey thing. Thanks in advance

 

[Freaky1]

If I may suggest,
Have someone sit inside and operate the a/c. Watch the front of your compressor. You're looking at the clutch plate on the front of the pulley. When they turn the compressor on, you want to see if the clutch (the disk) just goes to turning the speed of the pulley (normal), spins/slows then spins (not a bad bearing but will soon cause one, its a pressure issue, over oil charge issue or dragging cyl... most common I see is over oiled causing seperation and near hydrolock when static). Next is it bouncing sorta, but then working. Adjust the clutch gap for that one. Easy to do.

Check the gap between the plate (ENGINE OFF AND DISABLED) and the pulley. Your average business card should just slip in there. If you can put 2 in atop each other, might wanna adjust it and relive some stress on the system, current on the mag and heat on the front in general (kills pulley bearigs as well as input bearings.

If it does need adjusted, either read up and do it yourself or take it to someone who'll actually do it right as most will just say it's working, leave it be. Wrong answer.

To adjust, you pop the bolt in the center of the clutch plate, remove the disk being careful to not drop any of the tiny thin washer like shims from it. To adjust a wide gap down, you remove a shim equal to the excess gap and reinstall / recheck.

Hope I didn't make something simple seem complicated, but there's good info out there.
Also, not saying this is your problem, but is common, easy to check and easy to fix.

Frank

 

[laneo9417]

Thanks for the info - I'll definitely check this out. It didn't make the noise last night leaving work so I'm hoping it was just due to the moisture and two days of sitting.

 

[laneo9417]

If I may suggest,
Have someone sit inside and operate the a/c. Watch the front of your compressor. You're looking at the clutch plate on the front of the pulley. When they turn the compressor on, you want to see if the clutch (the disk) just goes to turning the speed of the pulley (normal), spins/slows then spins (not a bad bearing but will soon cause one, its a pressure issue, over oil charge issue or dragging cyl... most common I see is over oiled causing seperation and near hydrolock when static). Next is it bouncing sorta, but then working. Adjust the clutch gap for that one. Easy to do.

So I got the chance to try this last night. When the compressor initially clicked on the clutch plate engaged at the same speed of the pulley with no loud noise. I did notice, however, that there was some minor rotation in the plate (rotated no more than an inch I would guess) after it stopped spinning when the compressor clicked off...not sure if this is normal or not. When the compressor clicked on again the plate spun fine.

I also noticed that the compressor itself was pretty dirty and covered in a reddish brown dust...I'm guessing this is dust from the belt? Is this a sign of wear and tear?

I would've taken some pics or a video to help me explain this but it was too dark last night. I plan on taking a look at this again tomorrow morning and snapping some pics/video in the daylight.

 

[koda2000]

So I got the chance to try this last night. When the compressor initially clicked on the clutch plate engaged at the same speed of the pulley with no loud noise. I did notice, however, that there was some minor rotation in the plate (rotated no more than an inch I would guess) after it stopped spinning when the compressor clicked off...not sure if this is normal or not. When the compressor clicked on again the plate spun fine.

I also noticed that the compressor itself was pretty dirty and covered in a reddish brown dust...I'm guessing this is dust from the belt? Is this a sign of wear and tear?

I would've taken some pics or a video to help me explain this but it was too dark last night. I plan on taking a look at this again tomorrow morning and snapping some pics/video in the daylight.

I believe the reddish/brown dust and grinding noise is from the a/c clutch slipping and metal dust rusting. if the belt was slipping it would be black/grey dust. if the compressor isn't giving you any problems, you can just replace the clutch. I had similar problems on one of my '00 Mountaineer 5.0L's. my hub was very worn, rattled when engaged and I had lots of the reddish/brown dust everywhere. a new clutch (which I got from Advance using a discount code) solved my problems. i decided to use a clutch of a different design to get away from the 3-pin OE design. I wouldn't bother with trying to adjust your old clutch, which is petty much the same amount of work as it is to install the new one. the new clutch includes a new electro magnet, a/c pulley, a/c clutch hub with bearing and adjustment shims. it wasn't that hard to change and hasn't given me any trouble since.

Tip: it's better to have a little extra shim space than not enough. I had to go back and add a shim the next day as the clutch was dragging while disengaged once it warmed up.

 

[Freaky1]

Spinning after the fact is normal as the high and low side equalize.
The reddish dush is a sign of heat. While not necessarily an all alarm sign, it is a good sign of too much heat. If your clutch gap is good, you might want to pull the belt from that pulley and spin the pulley. Listening for a gravely sound. Then you want to see if there's front to back play. Either of these would be a pulley bearing on its way out.

First make sure the gap is good (if not, wait till the bearing check to correct). Then check the bearing.

If the bearing needs replaced, it's a matter of removing a couple snap rings once the disk is off.

Btw, from shims to bearings, all can be found in Napa's paper catalog if you find one not scared of phsical pages that turn.
If so, ask to see the catalog, it's pretty simple.

On that note, next time you're at a parts store, ask for a free gates multi vee belt check gauge. Since these felt based belts, chunking and cracking isn't a measure anymore. It's a tiny tool that lives happily in a glove box.

 

[laneo9417]

Still have not had the grinding noise occur since last week but here are a couple pics of what my compressor looks like:

I checked the clutch gap with a business card and it checked out fine - one card fit perfectly in there where two definitely would not have.

I'm going to be driving my Ex a lot more now that winter is on its way so I'll be monitoring this. Thanks to you guys for your input.