Rad fan running constantly, 75 club se ctdi
 

Sorry if this is a repeat post, but i cant find a post relating to the problem. I have an issue with the radiator fan running constantly, this causes the temp guage to barely lift from cold. Any ideas on a fix for this? Fan sender possibly? Thanks

I would say the fan control relay in it's control box attached to the fan cowling is stuck closed, try tapping the box if possible as a temp measure. Needs a new relay get an uprated one either 40 or 60 amp, to change bumper has to come off to get the fan/cowling off or at least on mine.

Hi Raymie,

This is well known problem with the diesel engine. I'm afraid that the cause is a failed PWM controller in the fan control box. This is the electronic printed circuit board which drives the relays. These are not available as a spare part unless club members Arctic or Jules happen to have a second-hand one. However, another club member with electronics expertise, FrenchMike, offers a repair service if you post it to him in France.

If none of those options is possible then it's a new fan and control box assembly I'm afraid.

Simon

You need to activate the on board diagnostics to see what the ECM is seeing the engine temperature as.

If the coolant temperature sensor (CTS) is defective or the wiring to it, then the ECM sees the temperature as -130 degrees Celcius, and the coolant fan operates continuously.

The OBdiagnostic how too HERE

It's a quick enough test to carry out ;)

Brian :D

Er, it should?
Mine runs all the time at low speed while the airco is on (now the warm weather's here) and I thought they all did that. Turn the climate control off and it should stop.

The engine not warming up won't be the fan, it'll be that the thermostat has cashed its chips. The fan has no additional cooling effect until the thermostat opens and coolant circulates through the rad. CDT / CDTi thermostats are notoriously unreliable. Do what everyone else (including myself) does and fit a secondary one in the top hose.

Tim raises something which isn't clear from your original post Raymie. Ensure that you have 'Econ' selected on the air con./heater control panel. Does the radiator fan stop now? Or does it continue to run even when you've removed the ignition key, centrally locked the car and left it for several minutes, even with a cold engine?

Simon

Hi. I have the heater switched off most of the time, does this mean the ac is off too? Is it worth checking any senders first?

Yes.

Does the radiator fan continue to run when you've removed the key, locked the car and left it for ten minutes? If so, I doubt that you need to check any senders.

Simon

Check what Brian says, he knows his stuff.

Normally the temp gauge not moving is a thermostat problem. However, if you have a faulty sensor who knows what the engine temp really is, the gauge can only show what it's been told.

The fan stops spinning as soon as ignition is turned off. As sensors ar cheap, surely its worth changing? I will be taking the inlet manifold off soon to clean it, where are/is the sender(s) located?