Hi, the engine fan on my '97 XJR continues to run after the engine is turned off. Started last night and I had to disconnect the battery to stop the fan.

Before I go to the mechanic and get the long story of how many issues could be causing the problem, ie fan cycling, thermostat, sensor, loose wiring, and he says it may take hours to find the problem, has anyone got any experience of this problem?

The engine is not overheating, the coolant levels are fine, A/C is good.

Any specific ideas as to why this is happening?

Thank you for you assistance, it is really appreciated.

 

Sounds like a thermostat - how long did you let it run on for before you unplugged the fan (sounds dangerous!)

 

Thanks for responding Sean B.
The fan was still running three hours after I turned off the engine. I disconnected the battery to stop the fan (not the fan - I don't know how to do that).

 

I know mine will run in hot weather for up to a minute or two after shutting off the car. I dont know if its on a timer or if it waits for the ECT data to go below a threshold value. If it does use the ECT reading, its possible the sensor is causing the data to be skewed or just completely out of normal operating range. Just an idea.

 

Thanks for the idea.
Do you know how to check the Coolant Temperature Sensor?

 

Sticking Relay?

 

^^That's another possibility. If the relay coil isnt energized power should not be getting to the fan, unless the relay is stuck closed. You check the ECT data by using a scanner to see the data parameters.

 

Any recommendations for scanner make and model to use on the 97 XJR?

 

Any generic scanner that is able to show OBD II data will be able to display the coolant temp sensor data. It would probably be wise to get a scanner that is CAN enabled too, it may even be required on these cars. I use a snap on mt2500 with CAN adapter, it only lets me do european vehicles as generic obdII since I dont have european cartridges for it.

Some others on here probably know what the best over-the-counter scanner would be to fit your needs. You may also get a scanner and find that this isnt your problem I wish there were scanners that give full dealer capabilities for all cars. Unfortunately, there is not

 

Thank you very much for all your help, it really is appreciated.

 

To close this thread:

Replaced fan control relay located behind front bumper, just below driver's side headlight.

Problem solved.

 

Good to see, thanks for your update