Hi all,
Sorry its a long post - please bear with me...
Vehicle: Defender 200Tdi
I have recently sent my 8 month old viscous fan unit back under warrenty as I believed it was not functioning correctly. The fan was much harder to turn when the engine was cold (i.e. first thing on a morning) than it was after the engine had been running for a while.
On Saturday I received a new replacement unit. I put it on and got the vehicle upto operating temperature (again reading hot on the gauge). I then switched off the engine and tried to turn the fan.
With 1 finger I could make the fan spin quite freely. Given that the engine is supposedly HOT (thermostat had definately opened and all water hoses where hot to touch) I thought that there should be significant resistance when spinning the fan????
In short this viscous unit is acting like the last 2 I have had so I surely this must be an OK unit.
At what temperature do these things begin to show signs or resistance?
This whole issue has come about because the gauge reads about 1 needle width off the end of the white on the gauge at 60-70mph - But never goes into the red, even at 80mph, and it never boils.
I have had a new (re-cored) rad, new thermostat and new viscous fan. I dont believe the head gasket has failed either (no visible signs in oil or water or at the exhause).
I am fairly sure that all my earths are OK and the gauge does not act in any strange way as you might associate with bad earths. However, just to make sure I am going to wire the sender unit and guage direct to the battery and see if that makes a difference.
Fail in that, are the sender units and or gauges prone to break down? Does anyone know the part number and cost for a replacement temperature sender unit??
Anti-freeze is at about 35% - 40% water mix.
Looking for some advice / pointers please...
Thanks Jon