My '97 4.6 auto trans 4x4 has a high pitched squeal in cold weather mostly when the engine is cold. It sounds like an alternator bearing but it has never locked up. Generaly after the engine warms up the noise goes away. At idle it is barley noticeable but gets louder as rpms build. It has made this noise for a good many years and even if I park in my garage, if it is cold enough it will still make the noise after I back outside and the cold air gets in the engine compartment. I replaced the idler pulley several years ago but it didn't help. Does anyone have an idea what it could be or has anyone had a similar problem? Thanks for any input on this.

 

Hi; The first thing to do with any accessory belt related noise is to first remove the belt, and spin all the pulleys by hand. If any of them feel hard to turn, or make a little noise when you turn them, you have a problem there. Try that, and let us know what happens.

 

Thanks for the input. I will have to wait till it gets cold here, could be late Dec. or Jan. before it gets cold enough. The reason I replaced the idler pulley was 'cause it was the cheapest thing to do. Again, thanks for your help.

 

I would check the tensioner pulley too. My uncles 99 merc had a squeel, I sold the car and my buddy's dad had the tensioner replaced. No noise now. It all started after I washed the engine and never stopped since. I'm almost certain you have this.