I have got the diesel and I have wired up the aircon fans with a manual overide switch to supplement the cooling. The fans still work as they were designed with the aircon but I can also switch them to full speed/half speed/auto. Auto has a thermal switch fitted in the radiator top hose.
It is never needed driving solo in UK weather, but towing in 40 deg C weather on the continent it has come on. My engine is also chipped and puts out nearly 50% more power.
I have also kept the viscous fan. It is far more powerful than the aircon fans.
If your vicous fan was noisy there was something wrong with it. I can't hear mine normally. When running hot, the viscous unit grips and the fan comes on with a faint roar under the bonnet. Yours must have been on all the time particularly if it reduced mpg. Best thing is to replace the viscous unit and re fit it.
There is a temperature sensor in the head that is wired back to the BECM and FIP and god knows what that monitors the engine temp. I know the engine power is cut automatically if it detects it overheating. Don't mess with it would be my advice. Could cause unforseen problems.
2000 Range Rover 2.5 DSE HP24 auto, uprated torque converter - JFearn chip, larger intercooler, removable winch, stainless exhaust, alloy radiator, Gen III's, Terrafirma +2" shocks, GG AT2/3's.
Full Fat Faultmate able to do all models.
- ex 1996 Discovery 2.5 300Tdi diesel auto
- ex-1982 Classic 3.86 Perkins diesel manual