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Loud low pitched whine in cold weather

I have a 2000 Mercury Cougar, 6 cylinder and when it is cold outside (40 degrees and lower) and I start the car in the morning it makes a horrendous whine that is low pitched and is definitely the sound of something that should be turning but is not. This hasn’t been a problem in the past while living in Florida but now that I live up north not only is it a more intense noise but I am worried about causing serious harm to the engine.



I can get the noise to go away by revving the engine (manual transmission so pretty easy) and just driving until the engine temp goes up. Not what I want to do if it is a serious problem.



My theory today after letting the noise go and then smelling around for a possible source of burning smell I could smell something right at the radiator fans. Am I crazy or is this a possibility? Any other ideas??



Thank you for your input.

Have you checked the tension of your drive belt(s)?

While I would describe the noise of a slipping belt to be a high-pitched whine, the belt is still the first thing that I would check.

Yep, the belts are all fine with no slip. It’s not a squealing noise that you get with a belt. I’ve owned some clunkers and have heard my fair share of slipping belts and strange noises coming out of the hood but I have never heard anything like this before.

Water pump?

Power steering pump? Get a cheap mechanics stethoscope at Harbor Freight to help you pinpoint the noise.

I’ve had that “low pitched whine” in Chrysler products and it was the power steering pump. In very cold weather the fluid is very viscous and in older pumps the vanes may not move smoothly.

Certainly worth checking out. Your mechanic will be able to identify the vibration.

The IACV can sometimes stick in cold temperatures causing a low, loud, resonance that will make you think your car is about to explode.

If you can rev the car a few times to get the sound to stop (or get it to start by revving the car to high rpms in neutral) than it is probably the IACV

On the newcougar forums we call it moosing and it’s a pretty common problem in cold weather

Could be the alternator. They have to work harder in cold weather to charge the battery after starting, and as the battery becomes charged after driving awhile, the alternator is not working as hard. Could account for it getting quiter after warm up.

Code Red . . . Doctor Motors . . . Report To The ER . . .

Grant, For less than $20 bucks you can have some fun and drive your neighbors crazy. Go to an auto parts store or Sears and buy and automotive stethoscope. Sears sells a nice one for fifteen bucks.

While it’s whining away carefully poke around with the probe on the stethoscope. BE CAREFUL. Don’t get you or it into any moving parts, belts, etcetera, and be prepared for loud noises as you probe. Try light touches and also try applying a liitle pressure to the probe.

You obviously can’t touch moving parts, but you can check alternator housings, stationary nuts on the center of idler pulleys, power steering pumps, water pump housings, and so on. You will learn what sound is normal and what is not or compare to another car that has parts that don’t whine. The scope will isolate the noise.

Good Luck & Have Fun

CSA