My radiators fans not turning on and the car keeps running hot. what to do. 2002 jaguar xjr

the thermostat is more than likely failed or the water pump. plastic impellor has broken, the easy way to test is to feel the radiator if engine hot radiator cold the coolant is not circulating, the favourite is the thermostat easy to change, common problem.the fan is controlled by the ecm, the sensor being in the engine. not the rad,

try opening the windows and turning on the fan. no heat, no a/c, just the fan. should cool down and blow the hot air into the cabin(thats y you roll down the windows). It will coll it off.

It would not be abnormal, so long as the fan does not come on when you switch on from cold. The fan's job is to draw air through the radiator to cool the contained liquid to a suitable working temperature. The fans sensor is activated by the temperature of the coolant. If this is a problem which worries you, try driving as gently and slowly as possible for the last mile or two of your journey. If things are normal the fan should not run on switch-off as that 'trick' will have allowed the coolant to get below the fan-kick-in temperature before you stop the engine. If your vehicle has a temperature gauge use the rteading as an indication.

http://wiki.answers.com/Q/Should_the_radiator_fan_run_after_the_engine_is_turned_off

the cooling fan running for a short time after turning off is normal.as far as the NO HEAT is concerned have the topmost hot hose clip undone and vent any airlock you may have.(pref a hose that is attached to the heater inside the engine bay).

The thermostat switch must be changed, the switch is sticking.

Probably the heater control valve, had same issue, started with one side not hot, then erratic, hot then cold while heat is set to hot, now both side are cold to lukewarm. diagnosed as heater control valve, common for jag s-types and x-types. located on the passenger side, down low the side of the radiator, it has several hoses into and out of valve, and a electrical connector.

Put water in the radiator

The fans are running trying to cool down the engine. Check and make sure cooant is full and start the car with radiator cap off and leave car warm up to make sure coolant is flowing. If the coolant starts to shoot out of the radiator, shut off and leave the car cool down and replace the thermostat. Then receck if you have no flow or it still runs hot have the radiator flow checked it could be clogged.

First suspect would be cooling fan controller. Big silver unit close to main fans. To check correct fan operation, leave it idling for a while, (best to do this test after it has had a run) and fully warm, then check both fans run up - they should go really hard after a while, the air flow will gradually increase to try to maintain a constant temperature. If they just run at a single speed, suspect controller, if only one runs, then the other fan or controller has failed (put multimeter across fan terminals to see which it is). Another possibility would be air lock in cooling system, these models are not prone to this, but it is a possibility, undo water pressure cap and make sure you fill until water is spilling down overflow tube, keep going for another pint or so, quickly put the cap on whilst water is still flowing down the tube. There is a second container at the front where excess coolant is dumped and returned when cold. If this is not primed, you can sometimes get a small vapour lock which can cause problems. Less likely is thermostat, these tend to fail in a predictable way, but thought I should mention it if all else fails.

look all the way to the back of that toward the rear of the motor... you should have some access to the drain plug... if there is no access you need to purchase the socket that will fit that... likely a torq type.

Robert