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General Information => Troubleshooting => Topic started by: Doug on February 12, 2007, 07:58:01 pm

Title: High pitch whine from somewhere under the hood?
Post by: Doug on February 12, 2007, 07:58:01 pm: It started today intermittently, soft but gaining in intensity, frequently enough to be concerned as I was on an empty highway in N. Ontario at -30C. It stopped after an hour when everything was good and warm. I wasn't stopping unless something failed totally. The car ran fine for the next 8 hours. Are alternator bearings a possibility???
Title: Re: High pitch whine from somewhere under the hood?
Post by: jtanguay on February 13, 2007, 01:05:49 am: Quote from: "Doug"
It started today intermittently, soft but gaining in intensity, frequently enough to be concerned as I was on an empty highway in N. Ontario at -30C. It stopped after an hour when everything was good and warm. I wasn't stopping unless something failed totally. The car ran fine for the next 8 hours. Are alternator bearings a possibility???

i get a nice high pitched whine when my boost hits around 5 psi, and climbs to 10. at 20 psi the rushing air sounds really neat.

failing pulley's sound weird... they can have a high pitch due to the fact that it is metal on metal. but more of a screeching noise than a whine. does it sound like the starter whine?? -30C is pretty damn cold...
Title: High pitch whine from somewhere under the hood?
Post by: Doug on February 13, 2007, 06:07:09 am: Rule out starter, JT. It was plugged in before starting with a block heater and an oil pan heater. There was no noise until after about 5 minutes of running. It almost sounds like it was boost related but with a middle C note to it. I wondered if it was the boost bypass valve whistling with a buildup of ice internally. Altering the throtle position would yield a change in note and intensity and sometimes make it go away temporarily. The belt was not slipping as it was adjusted the day before. Usually alternator bearings get noisy when they are hot? Any ideas?
Title: High pitch whine from somewhere under the hood?
Post by: jtanguay on February 13, 2007, 07:23:24 am: i didnt think it was starter at all.. just asking if the whine sounded a bit like it... (i should have said does it sound like a power tool whine :wink:)

good way to rule out the alternator is to just take the belt off and drive around... (easier said than done with a/c model though...)

do you have the stock air filter or a cone filter??? with cone filters you can really hear the motor, and the stock one really quiets down the motor a whole lot. the el cheapo one i put on mine really 'opened' up the motor so to speak... noise wise :lol:
Title: High pitch whine from somewhere under the hood?
Post by: addautomotive on February 13, 2007, 11:03:31 am: Probably a cat.... poor thing is scared $chitless.
Title: High pitch whine from somewhere under the hood?
Post by: RabbitJockey on February 13, 2007, 08:02:46 pm: possibly your speedo cable?
Title: High pitch whine from somewhere under the hood?
Post by: jtanguay on February 14, 2007, 12:46:49 am: Quote from: "addautomotive"
Probably a cat.... poor thing is scared $chitless.

funny story... my sisters cat ran into her car and on top of the exhaust pipe... :lol: damn cat took forever to get out... on a hot day too! good thing it had a chance to cool off a bit too!!

hmmm yea speedo's make a weird sort of clicking sound... not really clicking but as if something was rubbing and making a bit of a tick.. gets louder with speed (obviously...)
Title: High pitch whine from somewhere under the hood?
Post by: Vincent Waldon on February 14, 2007, 09:24:28 am: I've seen a high-pitched whine a couple of times... usually when really cold out and then disappearing over time.... only somewhat related to engine RPM strangely.

The first time it stayed long enough I started to disconnect things one by one... altenator, power steering/water pump... still whining.

In both cases it was the timing belt tensioner telling me that it was about to go south... not so much of a problem with my gasser but a big deal on my diesel.

Might be worth checking... any idea when your tensioner was last replaced ??
Title: High pitch whine from somewhere under the hood?
Post by: burn_your_money on February 14, 2007, 10:52:46 am: I also get a high pitched whine in the cold, usually once I first start out and for the next 5 minutes. It remains the same when I press the clutch pedal in, so I'm assuming it's not something on the engine
Title: High pitch whine from somewhere under the hood?
Post by: Doug on February 14, 2007, 11:10:50 am: Thanks for that idea, Vincent. The idler was replaced with a new one when I replaced the timing belt less than 5k km ago. I suppose that it is possible that it is defective but I will wait a bit and see. Maybe it was assembled with insufficient grease but you would think that if there was a problem that it would crop up when things were hot.
Title: High pitch whine from somewhere under the hood?
Post by: jtanguay on February 15, 2007, 03:03:05 am: i was just wondering... but could it be possible that it is some sort of intake/exhaust leak??? a small enough hole should give you a bit of a 'whistle'... like a kettle with boiling water??? :wink:
Title: High pitch whine from somewhere under the hood?
Post by: Doug on February 15, 2007, 06:03:46 am: That is what I have been thinking it would be but can't see anything obvious. Thought that maybe someone out there has had a similar situation.
Title: High pitch whine from somewhere under the hood?
Post by: jtanguay on February 15, 2007, 11:12:56 pm: Quote from: "Doug"
That is what I have been thinking it would be but can't see anything obvious. Thought that maybe someone out there has had a similar situation.

well when my car overheated i heard a whistling noise ... 'twas a terrible day!!!