Hi Folks - I'm hoping someone can help. I have a squeal that I am pretty sure is coming from somewhere in the A/C compressor/pulley assembly. The trucks squeals on start up (more so when it is cold/damp outside) and then sometimes as I am driving. It doesn't matter if the a/c is on or off. I have also noticed that, while driving, the squeal occurs when I take my foot off the gas. At this point I have replaced the belt, the tensioner and the a/c pulley. I am about to change out the shims to see if that works, but also was wondering if it is possible for the clutch hub to wear down and go bad.

Thanks for your help!

Dave

 

Remove the belt and test feel each drive for roughness and resistance.
Likely the A/C clutch or, the Alternator or tension plulley if it's that loud.
Good luck.

 

I would run it for a few seconds when belt is off, to rule out the chance of cam/crank position sensor.

 

my 01 has a high pitch whine on a cold start. By cold start in Canada I mean below -30.

The first time I heard it I was worried. But then I saw 2 other f150s of the 97-03 flavor do the exact same thing so I just figured it was normal for that kind of cold.

 

Thanks guys. I'll try those

 

I had the tensioner pulley on my 03 Supercrew go bad. It was whining like a power steering pump going out. It did it constantly though.

 

Is it possible for the clutch hub to go bad?

 

So I changed the shim in the clutch hub and got no difference. I took the belt off and the noise went away immediately. I spun all the pulleys and no resistance from any. The tensioner is new. The alternator is new. The belt is new. The ac clutch bearing is new and the shim is new. (not all of that has been replaced due to this problem by the way)

I did notice a little play in the water pump pulley but when I sit under the truck and listen for the noise it doesn't seem to be coming from there. I think the only other thing I could replace is the Idler pulley.

Do ac compressors squeal when they are going bad? It still blows super cold.

Thanks for any help. I am so frustrated with this now.

 

Two more things that may help....1) the squeal is much worse when it's cold out. 2) it occurs on start up and on the deceleration of the engine or if I just barely rev the engine and hold it there.

 

Mysterious squeal complaints remind me of the ordeal I had to discover harmonic balancer at fault. Dealer & local recommended mechanics came up w/the usual suspects, but missed the rubber ring in crankshaft pulley.

Try painting a line across the rubber on harmonic balancer. After it squeals look to see if pulley has slipped by checking if paint still lines up.

In my case timing mark was nowhere close & pulley had slipped rearward until it rubbed against front of motor. The small misalignment made belt fight AC pulley producing squeal upon acceleration.

 

Thanks Club. I'll try that. Do you remember how much it was to have it fixed?

 

After dealer & mechanics failed it became a DIY project. They're solutions were new belt, replace tensioner, suspect fan clutch.

Correct harmonic balancer was a bit difficult to find & cost nearly $70. Also replaced seal behind it. Was quite a chore having had no experience w/4.6L, suspect w/special tools & experience & no surprises it could be R&R 2-3 hours.

Note; if that seal is leaking there's even more reason to suspect harmonic balancer.

 

So no luck on the harmonic balancer. The line was right where it started. I even exchanged the old tensioner for a new one and replaced the idler pulley. I am all outta ideas.

 

Try marking the power steering pully, draw a line across the pully over shaft, see if your pully is slipping on the shaft

 

Try shooting water from a spray bottle at each separate pulley to hear if the squeal changes pitch. Let belt dry between each check to get the squeal back. Watch you don't hurt yourself with the engine running.

It is possible for the grooves in any of the pulley's or balancer to wear to a point even new belts will squeal.