well not permanently - they seem to stop after 3-4 hours. And that is only after a short run, we're not talking 3 hours on the motorway, so the engine isn't very hot.

And at the same time, air con has stopped blowing cold air.

Checked all the usual things like compressor clutch (I still have one and it is properly tightened up) and the functioning of the various flaps.

But the compressor doesn't appear to be starting at all so I'm assuming that the permanent cooling fans and the uncooperative air con are connected.

Any suggestions?

I think the operation of the fans is controlled by the coolant temp sensor, but I could be wrong. This isn't part of the air con control system, however it sounds like you've lost pressure on that score. You've not hit a big stone or something like that?

A fault code scan would be very helpful, I think...

No fault codes from the aircon - well intermittent fault on the cabin fan but can't see that having an effect. Just at the moment it's on full blast as there's no way it will reach 20C without the compressor kicking in.

And it's got plenty of gas according to Vagcom.

IIRC the rad fans are controlled by a seperate temp sensor that fits to the radiator, not the coolant temp sensor that fits in the coolant pipework. Has the coolant been changed recently? Any chance of an air lock in the system? That is usually the case if you can only get hot air out of the blowers.

Thanks for the reminder re. the rad sensor - yes, it is different to the one that I was talking about. Can you get the car in the air - if so, what happens if you disconnect the sensor? (Watch your fingers on the fan blades!)

And it's got plenty of gas according to Vagcom.

How do you check in vagcom ???

Will try disconnecting the sensor.

Quite right about Vagcom, I was still thinking about fault codes.

If there was an airlock, would that affect the temperature as shown by the dial on the dashboard as well? That is still rock steady straight up the middle.

I don't think that the aircon is blowing hot, except when you turn the temperature right up, air its just blowing ambient air (which is quite hot at the moment).

Have to investigate that as well. just seem to have been driving at hotter times of the day so the blower is just on fairly high.