Well the other day while I was in a drive through my truck started squeaking really bad. I turned the truck off and cranked it back up and it stopped. Few days later it started again and does it until about 2000 rpms then stops. Today while I was going to work it did it so I got the video camera out and recorded it. Its coming from under the truck. Not really in the engine bay. Only does it while the engine is warm.

I was in a hurry to get to work so I couldn't really do much. I sprayed WD40 on the under of the serp belt to see if it might have been the belt and it didn't change at all.

Anything know what it might be?


http://www.youtube.com/watch?v=9LnwHMiDj_s

 

First of all don't spray WD40 on a serpentine belt well even a V groove for that matter. WD eats rubber and it will cause the belt to slip.

The noise sounds to me like a pulley going out. Does it still do it with the AC is on? If you turn on the AC and it goes away it could be the clutch on the compressor. It could be the idler or tensioner pulley.

Take the belt loose and turn the pulleys you can by hand and see if any feel rough.

Something comes to mind though. When my smog pump went out it sounded a lot like that.

It looks like one of your O2 sensors isn't plugged in.

 

Yea I was in a hurry and just wanted to spray something on there to see if it would quit. Yes it still does it with the AC off. I was thinking it was the smog pump too.

It isnt loud under the hood just when you get under the truck.

Yea my truck had a MAF conversion and that was 1 of the extra O2s.

 

I'd pull the belt off like mentioned and check the feel of the pullies. I would also fire it up with the belt off to see if the noise persists. That would tell you if it was related to any pullies as well.

 

I'd have to agree here- pull your belt off and start checking pulleys by hand. It could be almost any one of the pumps. But one thing you might also try if you don't find anything that way is to run the engine, and then VERY CAREFULLY use a can of WD40 [or similar lubricant] with a straw to spray any exposed shafts on the pumps. Like the smog pump has a small amount of shaft showing.

But like I said, be VERY EXTREMELY SUPER EXTRA CAREFUL, because this can be done safely but you have to [obviously] watch yourself. I've been able to use this method a number of times to diagnose squeaky bearings. Even if its a sealed bearing it should draw in just enough of the lubricant to change the squeak or eliminate it.

 

Ill try that. Hopefully I can get it to start squeaking again and then take the belt off.

 

You mean it's not doing it all the time? If this is the case, does it only happen if it rains or is really humid out? If so, I'd bet on the smog pump too- mine does that all the time.

 

Yes it only seems to do it when its hot and when at the worst time when alot of people are around Its done it randomly everyday so far.

It did it again today so I went home and pulled the belt off and checked all the pulleys. They seemed fine. cranked it up and it didn't do it. Put the belt back on and it still wouldn't do it again..

Im thinking its the smog pump too. The sound is coming from under the truck near the cats. Not in the engine bay.

 

Something else I thought of- if you have a long screwdriver or steel shaft of some kind, you can use that to help isolate it. When it starts squealing, place the tip of the screwdriver against the smog pump and the handle against your ear.

It may not work as well with squeaking [I normally use this to help isolate engine knock] but the sound of the squealing should transfer thru the screwdriver to ear. If it's the smog pump you won't hear the sound transfer from any other component.

 

Through out bearing screaming-Just Shoot me ? Starter drive not releasing every time ? I have used a piece of swimming pool filter flex hose to be able to listen to stuff with less chance of decapitation . I bet the smog pump could make that noise, just sounds like its comming from down and bellhousing area? At least on the vid.

 

You can get a mechanics stethoscope at most autoparts stores for a few bucks. I have one and its nice to have.

http://www.amazon.com/Lisle-52500-Me.../dp/B0002SQYSM