C4 Engine Squeak
Thread Starter
Intermediate
Joined: Oct 2014
Posts: 28
Likes: 2
From: Phoenix AZ
C4 Engine Squeak
I have a 1993 C4 with 138k miles on it. I was idling on a red light, in drive, as I heard a squeaking sound coming from the engine. I then put the car in neutral (as I was still idling at the red light) and the squeaking noise stopped. Then once I put it back into drive after the light turned green, I suddenly heard the squeaking noise again. Could this possibly be one of the pulleys? And if so, if there a certain way to tell which pulley it is?
Thanks,
Ray
Thanks,
Ray
Race Director
Joined: Feb 2003
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From: Kingman AZ
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Sometimes you can use something such as a wood dowel as a stethoscope. Have someone inside the car with the brake on while you cup one end to your ear and place the other end up to different parts of the engine. Be careful with moving parts though!
Instructor
Joined: Aug 2014
Posts: 144
Likes: 2
From: Ca
Get some belt dressing spray down belts pulies top bottom let sit! Fire up! After driving if you still here squeick it's a vacum leak! Grab WD40 start spraying vacum lines when engine speeds up that's your leak! Just saying bra!
Le Mans Master
Joined: Oct 2004
Posts: 5,841
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From: CLT, North Carolina
You can also use a 3' length of rubber vacuum hose for a stethoscope. Move over and around the engine and you'll quickly find the source. The wooden dowel or a long screwdriver with one end on part of the engine and the other cupped to your ear works well for finding an internal noise source. Vacuum hose works well for finding external noise sources. 
Race Director
Joined: Aug 2000
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- NEVER spray belt dressing on serpentine belts or associated pulleys. vacuum leak = squeak - ??? WD40 - WTF?
Instructor
Joined: Aug 2014
Posts: 144
Likes: 2
From: Ca
Ok new to me bro! No belt dressing on belts? Then why do they make belt dressing? Wd-40 takes place of small vacum leaks and allows you to find them! I do want to know been doing this for years now and never had a problem! So WTF ?
Last edited by Rockcrushervette; Feb 6, 2015 at 09:35 PM.
Drifting
Joined: Dec 2007
Posts: 1,329
Likes: 17
From: woodbury new jersey
I had a lot of squeaking at similar mileage as your car, ended up being the idler pulley. then later had squeaking in my 2001 Silverado, ended up being a tensioner pulley. I say take the belt off and spin the pulleys by hand, both times I was able to notice a grinding/dragging from the bad pulleys, showing which was the culprit
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Race Director
Joined: Aug 2000
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NEVER spray belt dressing on serpentine belts or associated pulleys.
I'd almost bet the directions on your can of belt dressing states not to use on serpentine belts.not sure how you equate engine squeaks to vacuum leaks -
- new one on me! ...and WD-40??? personally, I would never spray a flammable liquid on a hot running engine, but WTF do I know? anyway, it's your car - have fun - 
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I have a 1993 C4 with 138k miles on it. I was idling on a red light, in drive, as I heard a squeaking sound coming from the engine. I then put the car in neutral and the squeaking noise stopped. Then once I put it back into drive after the light turned green, I suddenly heard the squeaking noise again. Could this possibly be one of the pulleys? And if so, if there a certain way to tell which pulley it is?
Thanks,
Ray
Thanks,
Ray
I had a lot of squeaking at similar mileage as your car, ended up being the idler pulley. then later had squeaking in my 2001 Silverado, ended up being a tensioner pulley. I say take the belt off and spin the pulleys by hand, both times I was able to notice a grinding/dragging from the bad pulleys, showing which was the culprit
Symptom remains. I believe that it is the tensioner pivot, so I will replace the tensioner assy (not just the pulley bearing) next.
Safety Car
Joined: Nov 2008
Posts: 4,328
Likes: 15
From: Jacksonville FL
I vote tensioner/idler pulley assembly as well. Take off the serpentine and crank it up for a few seconds and see if the noise disappears and you will know if its an external accessory pretty quick. If it does stop, spin each accessory by hand and feel for roughness and excessive play.
Good luck!
Good luck!
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
Sometimes the steel probe on those engine stethoscopes don't work as well locating some squeaks as removing that piece AND the diaphragm and probing with the open end of the rubber tube. (I wound up replacing a perfectly good PS pump as result. Ended up being the water pump after all.)
As for what to spray on ANY belt suspected of squeaking, good ol' dihydrogen monoxide (aka H2O, aka water) form a spray bottle works instantly w/o any lasting ill effects.
As for what to spray on ANY belt suspected of squeaking, good ol' dihydrogen monoxide (aka H2O, aka water) form a spray bottle works instantly w/o any lasting ill effects.
Last edited by Paul Workman; Feb 10, 2015 at 06:32 AM.