jweber

Looks like everyone says its the secondary air pump relay. Just picked one up this AM for $37 and will see if that takes care of it.

atlasrising

Hello to all.. i noticed something in my 96 audi A4Q.

the auxiliary fan keeps running on high. the engine warms up, and the aux fan starts going. it shuts off when the engine is turned off.

also. I noticed that even with the engine running the main fan stops spinning when the auxiliary fan is on. it spins freely, but slows down and just barely turnes, almost stops. I put the car in gear and drive a short distance, and the main fan starts up spinning again normally. then parked/idle, the main fan slows down, auxiliary fan turns on.

I recently had a garage diagnose that there's a bad thermol fan switch.

can't seem to find any other reading about this issue, unless this is normal. any input? or forum links discussing audi fan/cooling.

TIA>.

AudiMick

The mechanical fan is a viscous clutch, they get weak at high miles and often don't engage fully.

The electric fan should be on low normally for AC, and the second speed should engage if the gauge goes more than one tick over (95C).

Depending on where you live that electric fan should rarely run on the high speed.

If you turn the AC off the viscous fan should be capable of keeping the engine at normal temp.

I think you need a new viscouus fan clutch and the electric fan is taking the extra heat load.

turbo510

My '96 needed a viscous fan clutch last year, and went to AutoZone in desperation because the original was chattering. It was around $80 and seems to work fine, just remember the nut loosens "clockwise". I also was surprised to hear the fan's air sound when in stop and go traffic, which I hadn't noticed with the worn-out original part.

AudiMick

I had chased weird random temperature problems for several months.

Scored one off of a totaled low mileage Passat v6 for $30. Eureka!

atlasrising

i disconnected the aux fan. the car runs fine without overheating. it doesn't seem to be needed, is it ok to drive around with it unplugged?

AudiMick

Overriding systems is nearly always a temporary measure.There is sometimes an un-intended consequence. Like overheating in traffic on a really hot day.

As long as you don't need the AC or defrost you could drive it for a while.

In demist mode the AC runs to dehumidify the air going to the screen.