Cooling Fan and Fan Clutch Replacement
The fan blades on most Range Rover models are plastic, and are proneto eventual cracking and disintegration. The photo at right, kindly supplied by Ron Beckett, shows a RR fan on which a blade is cracked to a dangerous extent. It would not be long before this one flies off and demolishes the radiator, puts a hole through the bonnet or worse.
Replacement is easy, and just involves unbolting the blade assembly from the viscous fan clutch. You might find it easier to remove the hwhole fan and clutch assembly first, by unscrewing the large nut holding it on to the fan shaft protruding from the engine. This is a 36mm nut. To figure out which way to turn it, look at which way the fan turns to suck air into the engine and turn the nut the same way to loosen it.
Viscous Fan Clutch
The fan blades are attached to and driven by a special viscous fan clutch that provides maximum drive to the fan when the engine is hot and much less when it is cold. The clutch It works by centrifugal force acting on the viscous fluid inside it. This part is fairly expensive ($200 or so), but does need replacing periodically. Operation is a bit of a mystery, and testing it is rather difficult. Some people have suggested shoving a rolled up newspaper into the blades but this is not recommended!! Probably the best test is a comparative measure of airflow through the engine compartment with the hood open when the engine is hot and cold. If you can't feel any difference the viscous clutch is probably shot.
To remove the clutch from the drove shaft you just turn the 36mm nut on the front of it. The direction can be figured out by the fact that the thread is designed to tighten itself when the engine drives the fan. SO look at the fan blades and figure out which way the engine turns. Then turn the nut the same way to loosen it.
For replacement parts information for both the fan blades and the viscous drive, see the Range Rover Parts Sources section.
If you have comments, suggestions or experience to contribute, please email John Brabyn