fan staying on

[commanderbond]

Hi,
Ownen an RS6 for 2.5 yrs now....love it. Last few months cooling fan cuts in after just a couple of miles. (It might be the AirCon fan (not sure). Never did it before. Also runs on for few mins after car stopped. Temp never goes above 90. Audi specialist (not main dealer as I don't trust them), changed a sensor which came up on their instrument diagnostic plug in computer thingy, but made no change. They say it prob should do this....I'm not convinced as never did before but they say it might have been u/s before and is now working as it should now they have changed the sensor...again...not convinced.

Can anyone advise if this is normal ? Thanks

Dave

[raceman]

Hi, i have the same problem, although with mine, most of the time if i stop the engine for a coupe of seconds and restart it will stop it.

Everynow and then if i stop for petrol or something after just a couple of miles, the fans will run on with the engine off although the engine not and turned off. Again if i start the engine, then turn it off again, it seems to go off ok. it only does all this from start up, at no other time (at the moment.....lol

It's both the front fans that are running. Anyone got any suggestions?


Cheers

Paul.

[RS6-4dr911]

normal, as designed.

[paul_23]

As designed. When AC compressor comes on an extra fan starts. When turn off, if the engine temp is over a certain value a fan carries on and a recirc pump cuts in to avoid certain components (like Turbo) getting heat sink and failing. Both cut out after a while when the temp reduces.

[commanderbond]

Thanks for the replies. I should have added..........the fans will cut in also when driving and a good air flow through the grill etc eg at normal motorway speed. (They are on more than off). Is this normal too when on the move....??

Thanks

Dave.

[ecain63]

Some info on the workings of the engine fans. They are independant of each other. The main fan comes on under different load to the one on the left hand side.

Fans
Two suction fans connected in parallel
(600 W and 300 W) are used to provide
cooling air. The fan control modules are
actuated by way of the engine control
module as a function of load

The control module for the 600 W fan is
integrated directly into the fan motor,
whereas the 300 W fan has a separate
control module/output stage. Different
conditions apply to actuation of the two
fans.

Triggering and duration of fan run-on after
switching the engine off are governed by
three different criteria:
- Average fuel consumption > 7 ml/s and
engine temperature > 220ºF when
engine is switched off
- Measured engine temperature greater
than 220ºF and ambient temperature
greater than 32ºF
- On switching off the engine, oil
temperature greater than 200ºF

[Lig]

Hi chaps,

You need to clarify if its the aircon OR the engine/rad cooling fans... My cars cooling fans used to run on for a good couple of mins even after a short trip, I thought it was normal however a few months later the temp went above 90, I booked it in and my specialist garage changed the thermostat and waterpump. It is now fine and when I turn off even after a long journey the fan will cut out after a couple of seconds and doesnt run half as much as it used to. I put it down to a duff thermostat. IF you are close to having the cambelt done then deffo get the thermostat and waterpump replaced at the same time...!!!!

Lig.

[ecain63]

By the book they should always do the thermostat and the water pump whilst doin a belt change. Garages are lazy and tend not to bother. Annoying if the thermo goes after a belt change and they charge 7 hrs labour again along with another belt kit.