l have a van 2000 chevy xpress 2500 v6 with a horrible,terrible squeal. It started suddenly one day on a humid morning about 8 months ago. It got gradually worse. I changed almsot every assembly. Except the a/c and power steering. I can not figure it out. A mechanic said he thought it was the crankshaft but i believe that to be bs because a bad crankshaft would probaly sound more violent then just a belt squeal.


I have turned all pulleys they all move freely. Only thing I noticed was the idler pulley is wobbly and the tensioner shakes a little. BUT i changed both of those so I dont why they are doing that


I believe the idle pulley could be the issue since it was not ac delco but an aftermarket pulley.

I need to get this fixed because the van is undriveable.

 

Use a mechanic's stethoscope or a length of heater hose to listen to each component to better isolate the source of the noise. Consider unhooking the belt and run for several seconds to see if the noise persists - that would remove all belt related hardware from the equation. Silly question - did you replace the belt & is it the correct one?

 

Yes I have changed the belt twice. I would assume its the right one. It fits pretty snug on the pulleys BUT I can move the tensioner a little bit with hand even with the belt on. I think I heard there is suppose to be a little play in it though for these vans
I have also took the belt off and the noise was not there. only happens with belt on and gets worse with rpms goinng up
I will go buy stethoscope.

This squeal is terrible, the harmonic balancer was wobbling but u replaced that and it didnt change anything noise came back after like 20 minutes or less.

 

+1 for stethoscope.
if you are sure the pulleys are ok...buy a oem belt from the dealer. aftermarket belts are junk. Watch out for mechanic bull****!

 

Jusr bought the stethoscope, will see what i find.

To clarify I have changed the alternator,idler pulley,tensioner,water pump,harmonic balancer and belt atleast twice,(cheap be 13 14 dollar belts) and when the mechanic told me it was the crankshaft was when I knew he was about to try and screw me or didnt have a clue. Cant be the shaft because the engine runs smoothly at all speeds and rpms.

I want to believe its the idler pulley because it wobbles but not so sure because I took one off a another van that doesnt have the squealing problem or wobble and my van still was squealing.

Nonetheless will go check it with the steth.

 

So with belt off and no squeal, you now know the noise is part of the belt system. What I might try if the stethoscope does not tell you, would be to take the belt off and find an electric motor that you could hook to a belt and spin each individual component, one at a time. This would also be safer than working around all the spinning engine components, and you would also have no engine noise in the mix.

 

Also not sure the pulleys are ok but they all turn freely.They could be glazed from the slipping but i truly dont think glazing would cause the very high audible whining sound in hearing.

 

Just checked couldnt find anything i tapped around all the parts I could reach

 

with the engine running and the squeak occurring.....spray the belt with brake cleaner...does the squeak stop when sprayed...if yes replace belt.

if you have rtv. put a dab of rtv on the belt and start it up...if the squeak is gone...replace the belt.

 

Yes if you spray something on the belt or put soap on it the noise will stop for a short while...I have cuanged the belt twice once after changing the idler pulley.

Ill go get a belt from the dealership and see what that does