Squel help?

I've got a bad squel coming from the front of my 4.0 (97). It sounds almost like metal rubbing metal and gets worse with higher engine rpm. Sound is not present with belt removed. The belt is a new gator unit that I put on with a new water pump. All pulleys turn free by hand with no binding or noises. I have tried adjusting the belt tension with no affect on the sound. The a/c compressor clutch is not engageing so I am leaning to that as the culprit. I gave the HB a quick look and didn't notice any seperation. It looks like the belt is catching and causing all the accessories not to turn as fast as the engine? I gave everything a good listen with a stethescope and couldn't determine where the noise was. Any help would be great

Once again, the most important (and one of the cheapest) diagnostic tools for your kit is a 3' piece of vinyl tubing, 1/2" ID or less. Stick one end in your ear, move the other end around the engine--standard warning of flesh, clothing, and moving engine parts applies--and it WILL lead you to the source of the squeal. Trust me, it works, and once you have used it you will wonder why you didn't think of it sooner.

Good luck.

I use a long screw driver to do what Joe mentions. It does the same thing, and has always proved to be an invaluable tool for locating noises. Just put the plastic handle up to your ear, and the other end on different parts of the engine. It will be obvious. Its like a stethoscope for engines.

Both the screwdriver and tubing is a good trick to use when finding noises. another good idea would be to take the belt off and try and see if any of the pulleys have play in it. since the clutch on the ac compressor is not engaging that sounds like a good place to start. and that will def give you a metal on metal sound

don't forget to inspect the harmonic balancer for separation of the inner and outer rings.

If the injection molded rubber insulation begins to deteriorate, you can get enough deflection of the outer ring to make the belt squeal.

Ok I went and rechecked my hearing test with the tube and still nothing conclusive. I did manage to get the compressor clutch to engage for a minute and the air came back to life for a short time. It is way worse with the a/c on. Harmonic balancer still looks good. I reinspected all the pulleys and everything else the blet touches and nothing seems to bind or have any play. The belt did stop turning coompletly once like the compressor had locked up but it started moving again soon there after. I'm leaning towards replacing the compressor but just hate to drop 200 if not necessary. I may replace the idler pulley also since it has about 120k on it and its not very expensive. Thoughts? Anything else to try befor I go drop some coin?

The belt needs to be really tight to be correct. If you can twist it more that 90 deg. it's probably too loose. Get a "Kriket-II" belt gauge from NAPA to be sure.
You might unplug the air to keep it from stressing the belt until you can get it looked at.

Tightened the belt a little more and it got alot better. Dont have a gauge yet but will definately get one. I also put the gauges on the a/c and it was a little low so I added some 134a and the a/c is working properly now. The noise is almost gone now but comes in when you rev it up sometimes but is only momentary. It may be due to a littl coolant that got on the belt during the waterpump change. I'm going to get a gauge and check the belt tension again. What should it read. The sound seems to be coming from the drivers side of the engine more than anywhere else. I'm thinking power steering pump or idler pulley

You're new here I see. You might try searching "proper belt tension" for this question and search other questions you might have.

There need four or more characters per word to work through NAXJ's search. CPS* works, CPS doesn't.

180-200 ft lbs torque on a new belt.

140-160 ft lbs torque on any belt that has been run for 15 minutes or more.

PhotographerMike said:

You're new here I see. You might try searching "proper belt tension" for this question and search other questions you might have.

There need four or more characters per word to work through NAXJ's search. CPS* works, CPS doesn't.

Click to expand...

Thanks for the insight. I searched through many pages of squeal problems and came up with some good things to look for. I guess the tension gauge everybody had recommended really does help.

The two I had were the idler pulley (most frequent failure) and the rear bearing of an alternator.
One trick I tried was to remove the belt then, using a portion of a belt sander belt, I spun each pulley using a 3/8 drill to drive the belt. This worked great to find the alternator bearing. It is in a location that is hard to get to and I wasn't able to use the hose effectively. I now have an automotive stethescope purchased at Harbor Freight for a few $'s.