Hi all, I have a '99 Blazer 4WD with 146K on it. It runs well but the last two mornings I have noticed a strange slight whirring/whining noise from under my truck. It's different from how it normally sounds but it's not a horriblesound either. Now it has been a little cold here lately, at least the mornings have, and that is when it started. The noisestops as soon as I pull out of my drive aftermyBlazerhas warmed up. I also don't hear the noise for the rest of the day even after theBlazer has sat all day inmy garage at work.I just wanted to throw it out thereto see if anyone else has any ideas or has experienced anything similaror if I am just being overlyparanoid about the sound.

Thanks for listening.
Dawn

 

The noise you describe sounds very much like mine. It comes and goes, mostly when its idling. Doesn't matter if it is in gear or park. Sometimes it gets relatively loud and other times it stops completely. All I know for sure is that if you remove the serpentine belt, in mine anyway, it will stop. This tells me it is in the A/C clutch or Power Steering pump, or water pump since I have eliminated the Alternator and idler pulleys by replacing them. I have a post elsewhere in the forum asking for advice on the same.

Here is a link to that post, in case I get any information.
https://blazerforum.com/forum/engine-transmission-35/bearing-squealing-type-noise-under-hood-28824/