Squeeky bearing, but which one ?

Chip3 · #1 (**permalink**) 10-29-2009, 10:36 AM

Hello,
I have a 2000 f-150 4.6l 4x4 with 142,000 miles on it and I LOVE IT !!

I start the truck (warm,cold,anytime) and there is a squeek from under the hood that fluctuates with rpm, disappearing completely while I'm driving at 30mph or more. (I don't notice it then, anyway)

I'll hear a distinct "click", then the squeek goes away. 4 seconds later, it comes back, for about 5 seconds then "click", the squeek stops. 4 seconds later it comes back.....etc.

The alternator is only 20,000 miles old and the belt is solid. I'm trying to think of what component would be associated with a click, but it is very distinct.

When it first started doing this months ago, I would switch the fan dial around to defrost then panel then floor/defrost etc, and the squeek would change tones. I guess thats because of the load difference on the pulley's when a component is engaged, but maybe this will help describe my issue.

Any thoughts would be appreciated.

Cheers !

LxMan1 · #2 (**permalink**) 10-29-2009, 06:38 PM

Sounds to me like the a/c compressor bearing is noisy. Noise changes as it is cycling on and off.

steve(ill) · #3 (**permalink**) 10-29-2009, 09:11 PM

yes, compressor clutch. when you startup the pulley is spinning on the bearing and you har the noise. when the clutch locks up, the bearing is not working, the pulley is locked to the shaft. its not the compressor, its the clutch. it could be the bearing has a problem, or it could be the clutch parts are dragging or touching each other. is it a tin on tin noise, or a bearing squeek.

Chip3 · #4 (**permalink**) 10-30-2009, 05:19 AM

Yeah, it sounds like a basic squeeky bearing to me, like it needs grease. So this compressor clutch is operational even without the a/c turned on? Was it because of my description ("clicking" on/off) that caused you to think a/c compressor versus something like the water pump pulley, etc,?

Is there a way to positively identify this as being the problem or not before I start repair plans?
Is there a diagram of this unit available because it's not in my repair manual ?
2000 f150xlt 4.6l v8 4x4 142,000mi

You guys are awesome,

Thanks

Chip3 · #5 (**permalink**) 10-30-2009, 11:13 AM

Just got back from Auto Lab. They charged $24 to look at it and concluded that the belt Tensioner itself had seized, not the pulley, but the tensioner assy, which is supposed to move a bit. Because of this, the belt is not getting proper tension and has become slightly glazed and squeeky.

I'm replacing the tensioner my self ($55) instead of having them do it for $220.

steve(ill) · #6 (**permalink**) 10-30-2009, 10:04 PM

that shows you how you can be tricked. a loose belt can slip under load, but work o.k. when just spinning freely. normally if the belt is loose, it will have a continuous squeel, not just when the compressor kicks on or out. i have checked for belt noise before by pouring a cup of water on the belt while it is running and squeeking. If the noise changes drastically or goes away for a minute, you know its the belt.--- great find.