Mysterious underhood squeal- ideas?

TheOdessa · February 8th, 2012, 12:01 PM

I am getting a loud squealing noise from the engine bay. I have a feeling it's the alternator, but I cannot pinpoint it as it seems louder when I put my ear close to the first two injectors toward the front of the car on the passenger side. Don't know if this is because the alternator sound is bouncing off the metal of the intake?

-Can I test the alternator by removing the belt and running the car? I am afraid if I remove the belt it might cause the engine to overheat. I guess I can always take the alternator to get bench tested
-Could the possibility be there that a failing injector squeals loudly?
-Anything internal such as a piston with a bad ring or not getting oil cause a squeal? I'm not sure why it'd happen so suddently.

76k on the motor
mods in signature
Belt looks new- new cracks or tears. Has Carquest stampings on it.
Alternator looks new, but it has a remanned sticker on it from Carquest so it's an aftermarket unit.

Tang Stang · February 8th, 2012, 12:04 PM

Yes, pull the belt and start the engine. Don't let it run long and you won't have to worry about it overheating. It could be the alternator bearings, but more often it's a tensioner or idler pulley bearing that causes the squealing you've described.

TheOdessa · February 8th, 2012, 12:51 PM

Thank you sir. I'm guessing spinning the idler or tensioner pully by hand will result in this squeal as it's so loud and there's no resistance behind it. If I find that is the root of the cause, should I not drive it til I fix it? I'm assuming the noise would be coming from failing ball bearings? I'm guessing simply buying a new pulley and replacing is all that's in store? Any special greasing of the pulley I should be aware of?

To take off the belt, should I wait for the car to cool to do it, or can I do it when the car's at operating temp. I want to remove the belt and test when I get home from work which is why I am asking.

Tang Stang · February 8th, 2012, 01:00 PM

Yes, the squealing noise is caused by failing bearings. If it's as loud/obnoxious as you've described, you should be able to determine which pulley is the culprit by feeling for excessive play in the bearings while wiggling the idler/tensioner pulleys with the belt removed. It is as simple as removing and reinstalling. You don't grease these.

When you get home from work, pull the belt, and start the engine. If the squealing noise is absent, you know that something in the FEAD is the source. If it is still present, you've just ruled out everything in the FEAD. You can do this test at operating temp, as you'll only have the engine running for thirty seconds at most.

TheOdessa · February 8th, 2012, 01:32 PM

Thanks man. I'll update tonight to keep people informed and maybe help someone else out with the problem.

When you say check the pulleys for excessive play, just wobble it? Would it squeal if I turn it by hand? Thanks for all the help by the way with my noob questions.

04MidnightGT · February 8th, 2012, 01:38 PM

Spray your pulleys one at a time while it's running with some wd40 and diagnose this!

dcook_14 · February 8th, 2012, 01:54 PM

Originally Posted by TheOdessa

Thanks man. I'll update tonight to keep people informed and maybe help someone else out with the problem.

When you say check the pulleys for excessive play, just wobble it? Would it squeal if I turn it by hand? Thanks for all the help by the way with my noob questions.

If the bearings are bad enough to be squealing like you say, they will wobble around when you check the pulley. I had a power steering pump going bad on a 4.6 that squealed like a pig, the pulley on that flopped all over when I took the belt off.

TheOdessa · February 8th, 2012, 08:28 PM

Well it ended up being this pulley

and it makes this noise when spun by hand
Video02082012201318 xvid - YouTube

What does this pulley do and why would it make this noise?

Tang Stang · February 8th, 2012, 08:43 PM

That would be the water pump. The water pump bearings are shot, and it needs to be replaced. How does the coolant look?

TheOdessa · February 8th, 2012, 08:49 PM

Damn damn damn

I'll take a look. Am I supposed to notice anything? Last I checked it was green. Could this failing water pump be the reason I smell a burning smell at times as I drive?

TheOdessa · February 8th, 2012, 09:03 PM

I have the early 2001 model mustang. What water pump do I use???

Tang Stang · February 8th, 2012, 09:04 PM

Green = good. Muddy brown = bad.

If it's a sweet burning smell, yes, it could very well be related.

You'll need the 96-mid '01 water pump if it's an early '01.

TheOdessa · February 8th, 2012, 09:07 PM

but do you know if it's 65mm or 87mm?

EDIT- Found it's 87MM. You da man Tang Stang!!!! Thanks so much!!!

February 8th, 2012, 12:01 PM	#1
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	Mysterious underhood squeal- ideas? I am getting a loud squealing noise from the engine bay. I have a feeling it's the alternator, but I cannot pinpoint it as it seems louder when I put my ear close to the first two injectors toward the front of the car on the passenger side. Don't know if this is because the alternator sound is bouncing off the metal of the intake? -Can I test the alternator by removing the belt and running the car? I am afraid if I remove the belt it might cause the engine to overheat. I guess I can always take the alternator to get bench tested -Could the possibility be there that a failing injector squeals loudly? -Anything internal such as a piston with a bad ring or not getting oil cause a squeal? I'm not sure why it'd happen so suddently. 76k on the motor mods in signature Belt looks new- new cracks or tears. Has Carquest stampings on it. Alternator looks new, but it has a remanned sticker on it from Carquest so it's an aftermarket unit. __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

February 8th, 2012, 12:04 PM	#2
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	Yes, pull the belt and start the engine. Don't let it run long and you won't have to worry about it overheating. It could be the alternator bearings, but more often it's a tensioner or idler pulley bearing that causes the squealing you've described. __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

February 8th, 2012, 12:51 PM	#3
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	Thank you sir. I'm guessing spinning the idler or tensioner pully by hand will result in this squeal as it's so loud and there's no resistance behind it. If I find that is the root of the cause, should I not drive it til I fix it? I'm assuming the noise would be coming from failing ball bearings? I'm guessing simply buying a new pulley and replacing is all that's in store? Any special greasing of the pulley I should be aware of? To take off the belt, should I wait for the car to cool to do it, or can I do it when the car's at operating temp. I want to remove the belt and test when I get home from work which is why I am asking. __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

February 8th, 2012, 01:00 PM	#4
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	Yes, the squealing noise is caused by failing bearings. If it's as loud/obnoxious as you've described, you should be able to determine which pulley is the culprit by feeling for excessive play in the bearings while wiggling the idler/tensioner pulleys with the belt removed. It is as simple as removing and reinstalling. You don't grease these. When you get home from work, pull the belt, and start the engine. If the squealing noise is absent, you know that something in the FEAD is the source. If it is still present, you've just ruled out everything in the FEAD. You can do this test at operating temp, as you'll only have the engine running for thirty seconds at most. __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

February 8th, 2012, 01:32 PM	#5
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	Thanks man. I'll update tonight to keep people informed and maybe help someone else out with the problem. When you say check the pulleys for excessive play, just wobble it? Would it squeal if I turn it by hand? Thanks for all the help by the way with my noob questions. __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

February 8th, 2012, 01:38 PM	#6
04MidnightGT Hardcore Enthusiast 2004 Mustang GT 12.9 @ 111.44 Join Date: Jul 2011 Location: Wichita, KS Posts: 1,262 iTrader: 0 reviews	Spray your pulleys one at a time while it's running with some wd40 and diagnose this! __________________ l Custom Hotside l TurboSmart l MHS l Hallman l On3 l BBK l Hellion l SCT l Flowmaster l Steeda l AEM l Tial l HPX l Hawk l Trickflow

February 8th, 2012, 08:28 PM	#8
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	Well it ended up being this pulley and it makes this noise when spun by hand Video02082012201318 xvid - YouTube What does this pulley do and why would it make this noise? __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

February 8th, 2012, 08:43 PM	#9
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	That would be the water pump. The water pump bearings are shot, and it needs to be replaced. How does the coolant look? __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

February 8th, 2012, 08:49 PM	#10
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	Damn damn damn I'll take a look. Am I supposed to notice anything? Last I checked it was green. Could this failing water pump be the reason I smell a burning smell at times as I drive? __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

February 8th, 2012, 09:03 PM	#11
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	I have the early 2001 model mustang. What water pump do I use??? __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

February 8th, 2012, 09:04 PM	#12
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	Green = good. Muddy brown = bad. If it's a sweet burning smell, yes, it could very well be related. You'll need the 96-mid '01 water pump if it's an early '01. __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

February 8th, 2012, 09:07 PM	#13
TheOdessa Chitty Chitty Bang Bang 2001 Mustang GT Join Date: Jun 2011 Location: Tampa, Florida Posts: 1,254 iTrader: 2 reviews	but do you know if it's 65mm or 87mm? EDIT- Found it's 87MM. You da man Tang Stang!!!! Thanks so much!!! __________________ 2001 Mustang GT 5-Speed God Created Man, but Sam Colt Made Them Equal

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