I have a 1997 F code Suburban and I have a noise coming from under the hood. It is a higher pitched squeaking that sounds like its a pulley. Now, I try to listen to it when the engine is on but obviously the engine makes so much noise that I cant narrow it down. I really think its the vacuum pump but Im not sure. Is there any simple ways to determine where it is coming from.

I would like to fix the problem before I lose a pulley somewhere and need to get towed.

Use the hose stethoscope. 3 feet of small hose, one end on your ear, move the other end around till the noise gets loudest.
Ted

This is how I track down noisy pully bearings. But please keep in mind...this is a little dangerous with all the moving parts.

I take a long screwdriver (around 24" or so) and put the tip of the screw driver at the base of each pully (on the block or mount) then carefully place your ear tight against the end of the handle. I've had them slip off where i was touching them to and hit the belt or fan but never had a bad outcome, just a scary moment.

Okay, here is the best way I have found to track the pulley noise down, take the belt and spin the various different pulleys by hand. I had two go on me at pretty much the same time. The vacuum pump was my main issue and found it out the hard way(I touch the pulley after it had locked up, a little hot). The idler/tensioner pulley is your usual suspect though. But for the love of god do it while it is cooled off. AND SHUT OFF!!!!!

Thanks for the suggestions. As with the screwdriver, would a long socket extension also work?

May be the belt, check the tensioner to see if it's at the limit,
if not, see if you can put a breaker bar in the square and start it
(careful, don't let it hit the fan blades) , then put a little more tension
on the belt to see if it stops - or spray some belt dressing on the belt,
if the noise stops, it's not a pulley

A socket extension would work,too. My personal favorite is a length of 3/8"dia hardwood dowel. If it contacts moving parts, it doesn't become as dangerous a projectile as a sharp screwdriver or such.

Check tensioner pulley first with engine off. Grab and rock pulley to see if there's play. Tensior pulleys squeal from the driver's side. Vac pumps knock from under the AC compressor.

A socket extension would work,too. My personal favorite is a length of 3/8"dia hardwood dowel. If it contacts moving parts, it doesn't become as dangerous a projectile as a sharp screwdriver or such.

thats a good idea. I'll have to try that next time

I like to use an engine stethoscope, they are cheap and superior to the ole screwdriver in the ear trick.

I like to use an engine stethoscope, they are cheap and superior to the ole screwdriver in the ear trick.


yup for $6.00 its a cheap tool to just have around. i 've had one for a long time, use it a lot .