Screaming heater

[glennalan]

In very cold weather, when I start the van and turn on the fan for the defroster/heater, the fan screams very loud.It lasts until the van warms up.Any ideas on how I can fix it?

[Kings-x59]

Question:
Does it make the screaming noise when it set for the heater only?



When you switch the a/c to defrost, the air conditioner compressor kicks in. The a/c compressor on my jeep did this. All may not be lost though. My mechanic suggested an additive for the system that internally lubricated the compressor.
He said he couldn't garantee that it would fix the screaching sounds it was making, but for $35 it was worth a try - compared to $1200 for a new compressor. The additive solved the screaching sound problem.
Sorry, I don't have the name of it since I didn't do the work. But, I'm sure your local mechanic will know.

I'd be suprised if the a/c fan motor was making this sound.
Try opening the hood and listening from outside the vehicle. Set the ac switch to defrost, then to heat, then to A/C. If it screaches on a/c and defrost but not on heat, it's the compressor.

[glennalan]

Hi,
It doesn't matter what is selected...heater/defrost/blend etc. it screams very load until the van warms up