Satcomguy1

Greetings fellow Audi fans. Have an odd problem. Airflow from any cabin vent changes drastically when turning steering wheel to left. As wheel is turned to right the airflow increases in relation to how far the wheel is turned. Any movement to left even from far extreme right turn wheel lock will slow flow down and then will even out. This only happens when car is in motion even at just a crawl but not when stopped. Fan speed indicator never changes. Can't be a short because no blown fuse and fan always returns. If loose connection why only on a left turn? Seems more like some sort of damper control but not sure how to proceed. Anybody seen this before?

silverd2

It's your fresh air fan motor.

It's laid out in a way that, with a worn commutator and/or stuck brushes (carbon build-up) that left/right turns are pushing/pulling the motor shaft (within it's play in the end bushings), causing the brushes to gain/lose electrical contact with a grooved-out commutator...a common symptom of a fan motor on it's way out or in need of simple repair (if you're lucky).

Mine failed completely 4.5 yrs ago ... I simply cleaned the carbon build-up from the brush tunnels (did not replace brushes or anything) ... it's still working perfectly today.

Possible fix:

quattroworld.com Forums: Hvac Fan...replace or repair ?

Replacement:

audipages Fresh Air Blower Replacement

Satcomguy1

Good info to know. I suspected motor was going out since I heard it dragging last night when parked in bright sunlight in my drive. While investigating the fan noise I noticed what looked like rust in my coolant overflow can. It had a 1/4 in. coating of oil on top of the coolant. I don't see any milkyness in oil pan or change in level so suspect it is tranny fluid. This just happened because I checked fluid level before a trip a week ago and it was good. Temp was in 90's and so car was warm(never got about half way on gauge) and A/C was working. I guess that trip was the last hurrah for both my cooling systems. I have read other threads that the oil could be either from oil cooler or from tranny cooler portion of radiator. Since no milkyness is shown yet and no easy way to check tranny fluid level I have to suspect the worse. Probably will have to pull the radiator and have it pressure tested and get the tranny fluid and filter changed.
Just when I was getting ready to trade the car in. I just replaced 2 tires, tie rod ends, and the fuel pump/ filter in the last month! My windshield and driver side rear window cracked on my trip from apparently heat since no impact marks or bullseye is present.

silverd2

About the coolant: If any (any at all) of the wrong coolant was mixed with the pink (red or purple, too) G12, it will quickly form a floating corrosive brown sludge, that can clog a heater core or the heater pump/valve unit and eat plastic/rubber fittings.

Beware of ANY parts store coolant that says it can be mixed with "any color coolant" ....it can NOT be mixed with G12 . Even many stop-leak products (with the improper base fluid) will cause the same damaging chemical sludge...even if the label says it can be used with ANY coolant ... usually, not true.

Cheers

Satcomguy1

Thanks for info on coolant. I know it is correct. I have never used anything but the red Pentosin. It has been a couple of years since I did my last flush and fill however. It is possible someone else added fluid but don't think so. The only people who have touched my car in the last 2 years besides myself were the guys who replaced my tires a few weeks ago and they were just a tire shop not a service facility.

Going to tear in to the blower this afternoon. I have called a couple of local parts store for a replacement blower and radiator and have struck out on both. They show part numbers but units are not available. Hope to clean commutator and possibly replace brushes. I have found some blowers for the A6 and A4 but assume the won't fit. Also did find someone online with a blower for a 3.7 L engine. Not sure if blowers are different for the smaller engine. Don't have the right part number until I get unit removed.

Spoke to a buddy who works in a transmission shop and he recommends plugging the radiator transmission line ports and installing a aftermarket cooler in front of condenser. This way you just flush the radiator and not replace it and you don't have to worry about fluid contamination again.

silverd2

The part # is 4D0959101 ... same fan/motor on all yrs D2 A8/S8 (97-03). They can still be found new at several sources (and a few used ones on eBay)...but new is about $225 and up.

One online source >>>

Audi Parts - genuinevwaudiparts.com
The part # is

Satcomguy1

Got the blower out and part numbers match what you provided. Definitely has a drag on bearings and lots of carbon dust. Brushes have not been removed but they look like they are close to done. Found a new unit online from Amazon and few other places. Price is around $235 with the shipping.

Was going to try to cleanup unit but cages are being very stubborn to remove and probably a hassle to find right brushes. Commutator has quite a bit of wear as well. Going to order new and move on to the oil in coolant problem.

Job wasn't that bad except for removal of the last 2 rear screws that cover the motor/cages. They were not fun. One screw head twisted off due to rust. Removed the cowl cover and wipers and that helps a lot but the last 2 screws require a offset drive and small hands. Going to replace the Phillips head screws with hex heads and that should make replacement easier.

Satcomguy1

Put new blower in today. Seems to be working ok. Thought I would get some improvement on airflow output with new unit but seems to be about the same. Doesn't dropout on corners anymore however. Yea!

What kind of symptoms do you get when the resistor pack goes out? Do you lose everything or just certain speeds?