View Full Version : Aux fan howling

02-08-2013, 05:04 PM
Searched and searched but found mostly AC related problems so here it goes.....

Upon starting my '01 1.8tqm if the heat is on auto there is a loud screaming if it is cold out or grinding noise (metal on metal). As the winter has progressed it doesn't male the screaming noise as much mainly the grinding. After a couple mins it goes away but it always happens if the heat is on when started. If I turn it off the noise stops. After opening the hood it looks to be the aux fan that is making the noise. Now the aux fan always seems to come right on. I thought it was something that kicked on when needed. After searching I found a lot of AC related problems with the aux fan but in the summer when my AC is on it doesn't make the grinding or screaming noise it just always seems to be on no matter what and sounds like a jet engine. So what is the problem and what needs to be replaced is it as simple as a fan replacement or do I need resistors and switches ect.

Greatly appreciated

02-08-2013, 05:58 PM
I'm a tad confused - is it the AC fan, or the aux fan?

02-08-2013, 06:12 PM
I'm the one that is confused I assure you. I don't know much about this aspect of cars. After opening the hood and looking down it is the fan to the left on the radiator. I guess my fan that's always on with the AC is a different one all together? Not really sure. Ask me to change brakes, oil, filters ect.or put on an exhaust I got it but when it comes to this stuff I'm lost

02-08-2013, 06:36 PM
You mean to the left when sitting inside the car? If so, that is your radiator fan and is always spinning because it is belt driven by your accessory serpentine belt. The other fan is electronically activated. The one that is on the right when looking at it from a view from sitting inside your car. Are you certain that it is coming from your belt driven radiator fan and not something like your power steering pump? They are right next to each others.

02-08-2013, 08:21 PM
No i meant left as if you we're under the hood looking straight down. If I was sitting in the drivers seat it would be the right one. Electrically operated because as soon as I turn the heat off one second later noises stop.

02-08-2013, 08:22 PM
I'm going to take a video tomorrow for you guys to show you so long as I don't total my car drifting around in all this snow tonight. God I love quattro

02-08-2013, 08:40 PM
That fan is 100% mechanical. I'm not quite understanding how the heater on would make the noise disappear.

02-08-2013, 09:23 PM
There is only one left and one right in a car, the left side of the car is where you drive it from in North America just to make things clear. If the AC compressor is turned on then the electric fan on the right side of the car will turn on. There isn't much to it, it basically works or it doesn't as long as it is good. I would first unplug the fan and then start the car and make sure you have the climate control set to where it would make noise and see what happens. If it is quite then you will most likely have to replace the fan motor because I don't think they are serviceable. If you turn on the recirculating mode then the AC will turn off the fan but you can't use the auto mode because it uses AC.

02-08-2013, 09:29 PM
^Whoops. My last post I was thinking he meant the belt driven fan.

02-09-2013, 06:35 AM
Mine is doing a similar thing, just have been too busy to change mine. The electric fan comes on anytime you are using AC. If you hit the "ECON" button on the climate control, it will turn off the AC and the electric fan. Mine is making a honking/resonanting sound.

02-09-2013, 07:45 AM
Yea sounds like and old car horn. Why does mine do it when the heat is on?

02-09-2013, 08:04 AM
I actually answered your question but maybe I added too many words, lets try it in point form

- You set the climate control to auto
- When climate control is set to Auto it turns the AC on
- When the AC is on the secondary electric fan turns on
- The secondary fan sounds like it is sacked so it makes noise when the AC is on

- Unplug secondary fan and turn climate control to auto and see if the noise is still there
- If the noise is not there it is most likely the fan
- If the noise is still there the it is most likely the ac clutch or the ac compressor front bearing or it could be the ac belt tensioner

02-09-2013, 08:15 AM
Thank you

02-09-2013, 09:53 AM
I actually answered your question but maybe I added too many words, lets try it in point form