When I first got my 2004 X350, the radiator hose blew off due to a cracked outlet sleeve.. The car got hot, and the fan came on to cool the engine. I replaced the radiator, new coolant and thermostat, but I never hear the fan run when I drive the car. It doesn't overheat, the coolant leval stays where it should be, but I just wonder if the fan should be coming on now and then. It never runs after the car has been parked and the key is off.. Is there a coolant sensor or relay I should check??? Brandon

 

Usually there are two conditions where a cooling fan will operate. One would be the obvious; that is when the computer reads an over-temperature from one of the coolant sensors and commands a fan to run. Some modern cars even have multi-speed cooling fans to reduce noise at idle. Not sure about the 04 XJ. I have one, just not sure about the fan.
The other condition is when the air conditioning compressor is commanded to turn on. The fan usually runs to move air through the condenser to cool the refrigerant in the system. Again, it might run at a lower speed to reduce noise.
If your vehicle is not overheating then all is probably well. Hope you can find some assurance that your XJ is operating properly.

 

Much depends on your use pattern. If you do a lot of town work and stand in heavy traffic with the climate control cooling the car, the fan would normally come on to cool the coolant and also the hot refrigerant gas. These fans don't make a lot of noise to occupants of the car.

If you arrive after a fast run, the fan normally comes on as the engine will be hot, but there is no longer a blast of air to cool the radiator from forward motion.

It is unusual for the fan to run when the car is switched-off; I've never had this with mine, anyway.

I don't think you have anything wrong to worry about, the car seems to be behaving itself, so just enjoy it.

 

The fan on this car is completely variable, and the PCM usually runs it in a low speed. The turn-on point is when coolant reaches 200-205F without a/c, and it should run whenever the a/c is on and the vehicle speed is less than approx 40mph.

The fan running after shutdown can occur under certain conditions and depending on which PCM flash your vehicle has. Mine does not do that until the weather is near 90 and I've idled in lots of city driving.