I have a 92 blazer w/ a 4.3 TBI. When its as cold as it is,( im in chicago) the engine makes a very weird "whirring" noise at times.

What would cause this noise with these temps? it only happens when its cold around 15 degrees F or below.

 

Can you tell what general area of the engine it's coming from?

 

Does it seem to get worse as you accelerate? and does it go away after the engine warms up? mines actually started doing something just like that this winter (same make and model), although it starts at probably 40 and below (dallas dosn't get much of that 15 degrees)

 

Mine does it when it drops below freezing, im at -20 on my coolant but it seems to come from the front end of the motor, it is def. belt related or somewhere in that area. It does have anything to do with the RPM it makes the noise from idle in park thru 4k rpms, same pitch and speed of the noise everytime.

As soon as it warms up it goes away.

 

Might be the fan clutch. I know on the 4.3 with the belt driven fan, they are noisy at startup, and get quieter as the engine warms.

 

It sounds like the clutch fan on the front of the motor, when it warms up the sound goes away, so yea I would say its the clutch fan also since mine does the same thing!!!

 

Its a good thing I have a few old flex-fans laying around from my hot rodding days then, im glad its prolly this, give me an excuse to get rid of the power robbing hunk of junk hanging off the water pump.

Thanks guys, ive never had to deal with clutch fans, they are usually the first thing to come off my newer used vehicles.

 

No problem man, mine is doing the same thing until it warms up so I might follow your lead and swap over to electric!!!

 

I wont go electric until I get a aluminum radiator and either the duramax or a 355 small block mountain motor between the fenders and the SFA on it lol. I had problems with the thermostatic controlled e-fans before and just hard wired em with an inline 50a toggle. I was gonna swap the clutch fan out for a flex fan, but its about -7 outside right now and not sure how well the job will get done if at all.

Hows the baby swimming ?