Ventilation Fan NOT stopping !

[byrlord]

Hi guys,

I have an V range Audi A3 1.9TDI and I have noticed that the fan is always ON !

From the time I turn on the engine until 5 mins after I turn it off.

Is this something normal ?? or is something to do with fuses, thermostat ?

Any advice very welcomed ..

Thanks

[MOTOW]

Please look at my previous thread it might help.
Check sensors,rad thermo switch and fan control unit under battery.

[byrlord]

Hi, thanks for your reply.

You said
"Well, after much searching and testing there are two faults.
The water pump was the original audi plastic impeller, so it now has the modified brass one, works great.
The other fault was with the fan control unit under the battery.
After I fitted those and a new thermostat all is well."

2 questions please:

1. is it necessary to change the impeller ?
2. Is it easy to change the fan control unit ?

Thanks for your info

[byrlord]

Its me again:

I call German and Swedish car parts and they told me that this part can only be bought from audi ... any ideas ?

[MOTOW]

First check the radiator thermastatic sensor its towards the bottom left usually ,take off the electric connector,the fan should not run,then bridge the terminals with ignition on ,the fan should now start.
If this happens it should be ok.
If you take off the small pipe off on top of the water expansion tank with engine running and cap off you should have a steady flow if not water pump suspect or blockage somewhere.
Fan control unit is held on by two 10mm bolts situated just in front of battery.
If you need one they are about £90 from audi.
A haynes manual is quite helpful.

[byrlord]

First check the radiator thermastatic sensor its towards the bottom left usually ,take off the electric connector,.

I tried to do this but I can't take off the electric connector.
I think that the cable I am trying to take-off is not the right one !!

Is there a possibility to explain this bit better, like how it looks and where it is looking the radiator from the top ?? Any photos on how the thermostatic sensor looks like ??

Another thing I noticed is that if you need to change the sensor you need to empty the radiator isn't it ?

Thank very much for your time ..

[MOTOW]

Yes you will need to drain radiator,take engine cover off from underneath.
There is a drain tap at the bottom of rad near side.
The stat switch is just above the tap , press the release tab and slide off,a screwdriver may help to prise it off.

[Just-Chris]

I have a similar problem on my 05 A3 2.0 TDI, the Big fan is running all the time (sometimes alternating between two different speeds) and the small fan doesnt seem to run at all, though i heard the small fan is more for the aircon which im not using now its getting cold.

There is a lot of talk about fan control units, thermostats and resistors inside the fan etc. Problem is trying to figure out whats relevant for your model.

This page is talking about a MIV golf which may or may not be relevant
http://uk-mkivs.net/forums/449470/ShowPost.aspx


AVIT in Slough have quoted me £400 to fix - seems steep!! £300 of that is parts and im wondering what they actually need to purchase?
Unfortunately though the car is under 3 years old, its way over mileage and im the 2nd owner, dont fancy my chances of getting anything under warranty.

My temperature guage is fine, the car does take a long time to warm up (20+ minutes), particularly if idling, but that seems normal given the fan issue.

[byrlord]

The stat switch is just above the tap , press the release tab and slide off,a screwdriver may help to prise it off.

I think I know now where it is but or it is stuck or it needs a lot of power to take it off !

I am bit scared of pulling it so I will send you a photo of what I think the thermo switch is ... just to be sure !

Cheers

[MOTOW]

The parts are all available from partco gsf or other factors get quotes, they are very cheap.
The work is very easy to do.
The only audi only part is the control unit which is held by two 10mm bolts just forward of battery.Undo bolts first from working in engine bay this makes it easy to take off connectors.
First thing take off the connector with most wires on it and try the car.
If the fans do not start warm it up and wait for them to cut in slow at 90+ degrees.
If ok the fault is probly a sensor on the air con system.