I have an 02 Explorer XLT with 164K miles. I am the original owner. Recently the passenger side of the engine compartment has developed an annoying squeak. The pitch is associated to the RPM of the engine. The higher the RPM the higher the pitch of the squeak. It seems to be louder near the underside of the front then near the top. I replace the serpentine Belt Tensioner and that did not fix it. The belt looks good, no cracks or frays, and I sprayed some belt dressing on it but it made no difference.
What do you recommend I try next ? Thanks in advance for any suggestions, ideas.

- Tom

 

Do you smell anything that smells like burning rubber or burning oil? If you turn the headlights on does the squeal get worse? If the answer to either of these is yes, then concentrating on the belt and belt-driven accessories is wise.

If you do smell something burning, make sure your air conditioning compressor pulley is spinning with the belt, and that the compressor clutch is not trying to turn with the pulley. If the pulley is not turning, or the clutch appears to be trying to spin, the compressor may be seized up or at least partially seized causing the belt to slip due to the load.

If the squeal gets worse with the headlights on, then it would seem that the belt is slipping on one or more of the pulleys. The belt is probably bad, or mis-routed.

I've also heard of other folks who have struggled to find the source of a belt noise only to discover debris caked in pulley grooves which cause noise as the belt passes over them. Often these folks indicated they VERY carefully used a wire brush across the width of the pulley grooves while the engine was running to clean the debris. You would certainly want to be very careful, and I'd also suggest wearing safety glasses and having someone nearby to shut the engine off in a hurry if something were to end up in the belts that shouldn't be.

-Rod

 

Rod, thanks for the reply.
I am starting to get a smell of burning rubber through the ventilation system. The squeal does NOT get worse when I turn the headlights on.
The air conditioning pulley spins normal and when I turn the A/C on the clutch engages and disengages normally.
Hopefully this will narrow the field of pulleys that maybe going bad.

- Tom

 

That would seem to narrow down the likely culprits. Since you are getting a burning smell and the squeal changes with engine speed, I'd suggest you purchase a new belt. If you have the tools to change it yourself, remove the old belt and spin each of the accessory pulleys and idler/tensioner pulleys by hand. If you run in to one that is really tough to spin (with the exception of the power steering pump and the crankshaft pulley) then you should plan to replace it as well.

-Rod

 

Rod -
I replaced the serpentine belt today. The old one did not look bad, no cracks, glazed spots or grease on it. When I took it for a test drive it was completely quiet, not a squeak heard. Later in the day I need to run an errand and as time passed it developed a squeak again. It is not as pronounced as before but it there and still changes pitch with the rpm.
All the pulleys turned freely when I had the old belt off and no sound, of course different when not under load and not at high speed.

Anything else you might suggest?

- Tom

 

You might consider cleaning the pulleys. I typed up what I know of the process in the last paragraph of post #2 above. Since the new belt was quiet for awhile, this seems like a logical next step.

-Rod

 

Get some lalundry soap and mix with a gallon of water. Wash the belt and pulleys as good as you can with a paint brush or tooth brush. Pour some of the water down the belt into the pulley grooves below. Start the motor and let it throw off the soapy water and run it arround. Shut down, wash with hose or pour another bucket of clear water over it.

 

Modern belts don't really wear like the old ones, they lose material without getting shiny and cracked like the old ones.
You may have a bad idler, water pump or power steering pump. I would recommend taking belt off and spin each pulley by hand. Look for extra shiny spots, wobble, and if they spin smoothly.

 

Harmonic Balancer? (Crankshaft Pulley)

http://www.explorerforum.com/forums/...d.php?t=302068

https://www.ford-trucks.com/forums/1...ing-noise.html
https://www.ford-trucks.com/forums/8...y-shifted.html