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?