squeaking noise

I have a squeaking noise coming from under the hood of my 99 bravada. I have replaced the belt, idler pulley and tensioner pulley, but still a squeak.

sprayed the belt with "belt conditioner" made it worse
sprayed the belt with WD40 and it goes away for a few minutes but comes back

How can I check the PS, AC, Water pump to see if they are causing the problem without replacing them. This noise is driving me crazy...

You might take the belt off and spin each by hand and pay attention to any drag...they should all turn smooth & free by hand.

I replaced the tensioner today and that was not the source of the noise :crying: I did spin all the accessories by hand with the belt off and they all spin freely, the alt had a little resistance, but I think that's only from the brushes ?
I put an old pulley on my drill and put the belt on it, then spun all the accessories, but the drill was too loud and I couldn't hear the squeak. How would the dealer/repair shop find where the noise is coming from with out replacing everything?

Has to be a simple way...

you can use a mechanic's stethoscope, a long screwdriver or a rubber hose. Just be very careful when the engine is running.
Something else to think of might be the tensioner itself, not just the pulley. If the tensioner is getting weak it will not put enough tension on the belt allowing pulleys to slip.

You might give the back of the alternator a fair tap while the engine is running to see if the brushes are squeaking.
Since we're kinda running out of options, does it squeak with the old belt now...I've had new belts squeak.

you can use a mechanic's stethoscope, a long screwdriver or a rubber hose. Just be very careful when the engine is running.

I will try that tomorrow

Something else to think of might be the tensioner itself, not just the pulley. If the tensioner is getting weak it will not put enough tension on the belt allowing pulleys to slip.

I replaced the whole unit just to be on the safe side. I even left the wrench in the slot and had someone start it so I could add tension to it, just to see if the spring was worn. Still Squeak - Squeak - Squeak

You might give the back of the alternator a fair tap while the engine is running to see if the brushes are squeaking.
Since we're kinda running out of options, does it squeak with the old belt now...I've had new belts squeak.

I will also try that tap on the alternator tomorrow, if it still squeaks I might end up doing the tap with a sledge hammer :grinno:

May be your A/C clutch bearings. My 2000 and a friends 1996 Bravada had the same problem. Its very difficult to isolate this. My friend was able to spray a little lubricant in his and the problem stopped but only for a few minutes, thats how he located it. He ended up replacing the A/C un it and the problem went away.