Thread: Viscous Fan clutch not engaging

BorgWarner Visctronic - YouTube


I dont know if the D4 is a borg warner unit but the operation would be similar.
Regards

Originally Posted by northiam

BorgWarner Visctronic - YouTube


I dont know if the D4 is a borg warner unit but the operation would be similar.
Regards

If the D4 unit is the same as that then there are many more things that Can fail than on a normal viscus unit and I would imagine that a replacement would be Much more costly as well.

Yes, but... far less than the cost of a slipped cylinder liner and wiped cam lobes

D3/4 2.7 liter has a viscous fan with electric override,one cooling fan only,no thermo fan.

completely different type of fan from the D2 viscous fan.

I don’t know what the 3.0 litre D4 has.

D2 has a viscous fan,and a separate electric thermo fan,which operates as per my previous post.

FWIW,the Puma has the same viscous fan as the TD5.

Viscous fans are filled with a silicone fluid that thickens on temperature rise,oils do the opposite.

The viscous fan unit is electronically controlled by the ECM to optimise fan speed for all operating conditions.
• NOTE: If the electrical connections to the viscous fan are disconnected the fan will 'idle' and overheating may result. The
ECM stores the appropriate fault codes in this case.

From manual^

The D4 2.7 & 3.0 appear to have to same fan?

I have had the car in recently and I don’t believe any fault codes were registered for the fan. It is definitely plugged in and does spin just not fast. Seems like I need to take it back and see if any faults have registered. Also get them to see if clutch is engaging.

Yes, D3 and D4 have same fan setup. There were cases of the electrical connectors to the viscous fan either corroding or otherwise failing. I suggest that is the first thing to look at.

BTW, the D5 (sorry, "All New Discovery") has a thermo fan - no viscous fan. That opens up a bit gap between the donk and the fan/radiator!

Cheers,
Rob

Just to Sum up, After the responses I ended up replacing the fan which did the trick and Now I hear that fan roar every now and then. Went back to auto elec for check of AC that he regassed. No leaks from ac. He hooked up his guages to see if the system is still over pressurising. With the AC on and car idling the pressure in the AC rises to a point where the fan clutch engages and you can feel the extra air volume being pulled through the radiator and the AC pressure drops immediately which it wasn’t doing before. I assume the car monitors this pressure and engages the fan clutch to drop the pressure otherwise the compressor switches off which I believe was happening before. So all up nice cold AC again and no replacement of compressor as advised by one of my indy’s.