Loud squeaking on a 93 gmc k1500
 

When I first start my 93 k1500 it runs normal. A few minutes after I start driving my engine starts to squeal and becomes obnoxiously loud. It is loud under the hood but is almost deafening when lying under the truck. Also when I turn the truck off it sounds like it is sorta of screeching to a stop.

I've replaced my crank pulley thinking it was wobbling too much and putting too much pressure on my other pulleys, the power steering pump and pulley, the tensioner pulley, and even my belt within the past two years. I'm beginning to think it's my harmonic balancer but I am not completely sure.

Any ideas or help would be a HUGE help.

Water pump?

Try running the engine with the serpentine belt removed just for a few moments. Remember, that belt drives your water pump and with it removed you have no cooling going on inside your engine, so only run it for long enough to diagnose your noise.

It takes too long for it to start making noise for me to take the belt off.

Okay, well try using a to listen to each pulley. Buy that I mean just touch the tip of the tool to the bolt on the pulleys, or by the alternator bearings, idler pulley bearings, etc. Find the loudest pulley and that's most likely your culprit. My money's on the idler pulley bearings being loud

Sounds like it may be the water pump only squealing once the thermostat has opened up?

See if you can't watch your temp guage and diagnose what temperature it starts... May want to replace the thermostat and PCV anyways because those are cheap and easy.

Spraying a TON of WD-40 on the belt and pulleys while the truck is running may get everything else to quiet down enough to help diagnose as well.

Sorry i'm not much help but I have ideas!

Okay so I thought I had it all figured out... I took off my A/C unit and replaced it with one I had lying around and to my surprise the noise stopped! I drove it with the original one still hooked up to the lines and held off to the side with bungie cords and just used the one I had lying around for a spare pulley until I could order a new compressor. I drove it like this for 3 weeks with no issues at all. I was finally able to get a new compressor and decided to replace the drier and orfice tube so that way the whole system would be warrantied. I replaced everything and had no issues for a little over 2 weeks. Today I finally went and got the unit charged so I could have a nice cold AC since it is starting to warm up in AZ.

This is where the fun began again.... I picked it up from the shop and after about 5 minutes of driving IT BEGAN SQUEALING AGAIN!!! I am going to go crazy trying to figure this out!

So does anyone have any ideas...

Oh and I replaced the torque converter and and idler pulley before the whole AC fiasco.

I replaced the thermostat and PCV along with the pigtail just to be sure and tried the WD-40 trick with no success. the water pump is the only pulley I haven't replaced yet but it doesn't make sense to me since once I replaced my AC compressor it worked fine until the system was charged.:confused:

Belt worn and or the tensioner is weak? When the A/C engages and puts strain on the belt, it starts slipping?

I once had a problem with a loud knocking sound coming out of the engine compartment. It would only make the noise when the AC was engaged. The sound seemed to be coming out of the compressor. Turn off the AC and everything was quiet. I picked up a new compressor, charged up the system and turned it on. The knocking came back immediately. Boy was I confused.
I then did what I should have done in the first place. I got a long screwdriver and placed the handle against my ear and probed the compressor with the other end. Very quiet. I probed the power steering pump which ran on the same belt and was directly below the compressor and the knocking was very clear. Changed the pump, fixed the problem. What that taught me was that the increased load on the belt caused by the compressor being engaged transferred the strain to a weak part, the PS pump.
I don't know if any of this applies to your problem but tracking noises can be tricky. Good luck and let us know what you find.

It could be the tensioner but the belt is new. It also makes the loud noise the entire time the truck runs, with or with out the AC running... I'll get my stethoscope out today and try to do some investigating.

I also forgot to tell you guys that the NEW compressor, when engaged, sounds like it has gravel in it. When it's off the pulley runs smoothly but when I turn it on and the clutch engages the compressor makes a loud grinding noise.

Replaced the belt and tensioner today which quieted the compressor quite a bit (no more sounding like gravel) but the loud squealing is still there after the truck gets warmed up. It is also throwing code 43...:mad:

I wonder if your whistle noise isn't a vacuum leak?

I found that the clips on my knock sensor pigtail had broken off so it wasn't seating properly which was causing the code. I ruled out the water pump and fan clutch yesterday also. My power steering pump is now the only accessory I haven't replaced in the past month and it has a lifetime warranty so I'm going to swap it out today. If that doesn't fix it I'm not sure what will...

Well it didn't fix it. I'm going to try to upload a video with the noise to see if anyone recognizes it

I also took the belt off today and decided I would try to drive it down the road and back. I found that it makes this sound with the belt off.

Well, I'm really confused and sorry I can't help... but that has to be annoying as 4^#^$&!

Extremely annoying. I'm thinking it could possibly be the oil pump going out or a warped cam which is causing my lifters to rub causing the noise..

Ya know what, I just now thought of it. I wonder if it's the viscus fan clutch ... try taking the fan completely off and running it to see what happens? Sounds like it resonates, like a twangy thin steel fan.

It's all been replaced though and it does it after driving a little without the belt on

Fan clutch activates when the radiator gets warm, and might spin while there's air being pushed through the radiator. Does it make the noise with the belt off and engine idling? Cause if you're driving without the belt on, I can see the air from the radiator turning the fan making noise.

Also I guess if you're going go go through the work of pulling the engine apart to figure out the noise, I guess it's worth taking out the torque converter bolts before you get too crazy. That way you can 100% verify that it it not coming from the torque converter or transmission. Just pull the starter, and take each bolt out and then slide the torque converter back into the transmission a little so that it clears the flexplate.

Well i replaced the torque converter and flex plate thinking that might be the cause and still no luck. Took it to the shop and the still have no idea... anyone have any other ideas?