Cooling fan help

[sworks]

Been reading some of the cooling fan posts but got a bit confused after reading so many. What is correct operation as i have only noticed 1 speed on my car. The fan cut in today when needed and sounded quite loud, when it cut out again i turned the air con on and it seemed to be the same speed. Is this normal as i thought the aircon speed would be higher? Sorry if this is a stupid post thats been covered but it's been a long day.

[T-Cut]

Assuming the engine coolant temperature is 'normal' or lower, the fan should operate continuously at 'slow' speed when the engine is running and the A/C system is switched to Auto. It should stop shortly after switching to Econ. With Auto on, the fan should not exhibit an on-off pattern every 30 seconds or so. If it does, it's faulty. The 'high' speed is basically for emergency engine cooling or if the A/C system becomes overheated. If your car is a late or facelift model, it will have a 2-speed fan. Earlier models are 3-speed. As to whether yours is running at 'slow' or 'high' will depend on the above criteria. A 'high' speed fan sounds like a hovercraft. The 'slow' speed is an audible hum, which can just about be heard when driving.
TC

[sworks]

It does sound like a hovercraft, but i was confused as i thought low speed for basic cooling and fast speed for emergencys and air con. Sounds like i am only getting fast speed? 53 plate pre facelift

[T-Cut]

Originally Posted by sworks

It does sound like a hovercraft, but i was confused as i thought low speed for basic cooling and fast speed for emergencys and air con. Sounds like i am only getting fast speed? 53 plate pre facelift

No, A/C normally requires only the slow speed fan. It will switch to high speed if the refrigerant system overheats, which it will if the low speed side is faulty. That's why it cycles on-off as the system cools, then reheats. Very bad for the A/C compressor. You may have a faulty 2-speed motor. Look through the front grill and between the fan blades in the 2 o'clock position. You may see a 3" long aluminium resistor mounted on the fan framework. If so, this has probably failed.

TC

[sworks]

Thanks for the info - if it's working ok so far, maybe it just hasn't got hot enough for the fast speed

[T-Cut]

Originally Posted by sworks

maybe it just hasn't got hot enough for the fast speed

Possibly. And at this time of year it may not do so. Leave car standing with engine running and A/C on. Keep an eye on the temp gauge and listen/watch for the high speed to kick in. If it does all's OK.

TC

[sworks]

Thanks for all your help

[Steven D]

Good afternoon all,

After having read of all of the posts concerning cooling fans, type, upgrades, etc.. I'm afraid to say I'm even more confused than before....

I new to the 75 fold and have owned my 03 1.8T for little over a month. I bought it with a very comprehensive (and suitably expensive) 3 year warranty.

The observations I have made are :-

a) When aircon is switched on the fan unit is also activated (at what speed I don't know but it's not turbine loud)
b) When aircon is switched off it deactivates (except during point (c) below)
c) When the car has been run for a while and I park up it seems that the same fan is sometimes activated. This switches off when the ignition is switched off.
d) Sometimes when the car has been run and parked with engine running and no fan present, if I then switch on the aircon the fan starts but does not stop by swtiching the aircon off again. It then stays on until I turn off the ignition.
e) The car operates always within the normal temperature range - i.e. bang on midway on the temperature guage
f) I have left the car on tickover from cold for about half an hour until the temperature reads normal and no overheating or fan cuts in. The only time the fan seems to activate (when not in aircon mode) seems to be when it has been out on a run, even on cold days like yesterday. It seems to be prevalent when parking/reversing up or sitting in traffic.

Is this me just being paranoid or should that low speed fan only just work then the aircon is switched on ?.

Any help would be greatly appreciated.

Thankyou all, in advance.

Steven

[kaiser]

I think it all sounds fine. The reason why it may start after you park the car, is heat soak. When you switch the ignition on again, the heat has soaked into the water around the sensor, and not been moved away because the engine is stationary. It will soon clear when the engine runs, and the fan will stop.
As for the temperature gauge sitting on normal, it will do that anywhere between 75 and 115 degrees.
Just keep an eye on water level and fan motor, as a matter of routine.

[Steven D]

Thankyou very much for your quick response and from so far away !.

My main concern was that even after a small blast (1 mile) in relatively cold conditions the fan would sometimes come on, even though the temperature gauge was sitting mid-way. Sometimes the fan starts as I drive up my estate road, never mind when the car is actually stationary/reversing into the drive. Does the 1.8T run naturally hot ?.

It also bugged me that when the engine is cold I can switch on and off the AC with merry abandon but when the engine is warm, once it's switched on the fan stays on.... For how long I don't know. That would be my next investigation.

I think I'm being a little paranoid - or maybe a lot...

Cheers

Steven

PS Sorry - just wanted to clarify that the fan does not seem to come on during normal driving - only when the car is slowed to park or stopped to reverse, etc...