ExpressvanMan2000

2000 chevy Express 2500 4.3 v6

Have a belt squeal that mysteriously appeared out of nowhere.
At first i only heard during humid or moist weather....eventually it progressed to hearing it all the time(over the course of a couple weeks) it would sometimes quiet down upon getting into a higher gear..

Got so bad to the point i had to soap the belt with a bar of Irish springs to drive...eventually that wore off.

Changed the belt tensioner and belt and it stilled squealed...changed the idler pulley and the belt again becuase the mechanic thought it might the idler...noise came back after about a mile or so....changed the alternator because the pulley was making a high pitched whine when turned so i thought for sure that was the cause! Nope noise still there and strong as ever....so far im out about $200 dollars in parts, not to mention i can't even drive my dame van because of this horrible noise...what is the deal.... I even took sand paper and sanded the belt down as the engine was running to rough it up and that still didnt help

Are my pulleys glazed, could the little bit of crud from the soap stuck on one of the pulleys cause this(i dounbt it since its not that much)could it be my water pump ?someone please help..2000 chevy express 2500 4.3 v6

Beau Oszman

The mechanic didn't poke around with a stethoscope for you first?

ExpressvanMan2000

No. He just assumed it was the idler pulley because he saw what he called hot spots on the idler pulley, I didnt really press him about it because he was working on other cars at the time and stopped to look at mine and he was certain it was the idler so i replaced it and the belt like he said.

SteveROntario

Did you use a quality tensioner? I spotted two belts on my 2004 6 liter. Can you get the noise to go away with load reduction (turn off the AC before starting?). I wouldn't touch the belt drive system with the engine running, you could easily lose fingers.

Beau Oszman

Second that, fingers/loose clothing/hair don't do so well around fast moving machinery. If you live somewhere with a horror freight or have a friend with a stethoscope, checking around with that might save more unnecessary PM work.

ExpressvanMan2000

Well I can always take it back to the mechanic im sure he has one, but i prefer to only go that route if im going to let him to do the workmay go ahead and buy one. Actually figured out limbs and fan blades dont go together today, thumb bumped the fan blade while sanding and the blade whacked the outside of my thumb pretty good....did absolutely 0 damage though. Im sure that was a sign to stop taking chances.

Also have not done a load test will give ita shot...and i bought a mid grade tensioner from gates. . Im thinking the tensioner may be cheap I just didn't want to spend $90 for the acdelco one. Also the tension on the belt seems kind of lose...i can move the tensioner with my hand when the belt is on.

GatorHawk24

ExpressvanMan2000,

Short story... Check the water pump with an automotive stethoscope and someone in the driver's seat who can responsibly adjust engine RPM at your command.

Long story... I had a similar-ish issue with my 2016. It developed a noise that I knew was belt related, but not the belt itself (it sounded more mechanical, like a bearing). I replaced the serpentine belt, the tensioner, and the idler pulley, since they were relatively inexpensive, I could replace them in my driveway in under an hour, that was the general area the noise seemed to be coming from. That didn't fix the issue. I went to a local Harbor Freight and picked up an automotive stethoscope and started probing around... word of caution, be extremely careful/cautious when probing a running engine, there's a lot of fast moving parts! I thought it might be the alternator, but when my son revved the engine, the pitch changed but not the intensity of the sound. The water pump was the very last thing I checked (of course, right?), and it was the source of my noise. Thankfully, my van was still within its power train warranty, so that was a blessing.

ExpressvanMan2000

Well i know mine doesnt have a warranty since it was a decommissioned fleet vehicle front at&t that i bought second hand from a janky dealer and i was real suspicious of the water pump but was skeptical it was the cause... really thats the only other issue it could or a pulley misalignment which i dont see.


And yeah im not looking forward to probing around with the stethoscope due to how close the fan blade is the accessories on these vans.

mountainmanjoe

@ Gator
So the pump bearing failed on a 2-3 year van? (how many miles?) Any idea why? Just defective?

GatorHawk24

The water pump was replaced at 52,000 miles on a (used) 2 year old van. It was still functioning, but the bearing was wearing out. Unfortunately, there was no clear reason (at least not one given by the dealership) why it was failing so early. Must've been defective from Chevy? It's possible that something happened with the previous owner, but when I inspected the van, I didn't see any signs of damage to any engine components (I think it might've been in a minor fender-bender (not on CarFax report) because the driver's side front fender looks like it was repainted).

I didn't check the water pump initially because I didn't believe it could be the problem. The sound was very audible inside the van and seemed like it was originating higher up on the engine (if that makes sense), which is why I started with replacing the idler and tensioner pulleys, then suspected the alternator could be the culprit. I didn't want to throw money at it changing parts that weren't bad, so I started probing everything with moving parts at various RPMs, which led me to the water pump.