The cooling fan on BMW X3 models is electronic and controlled depending on engine temperature and a/c operation. The main job of the cooling fan is to draw ambient air across the cooling fins of the radiator to lower engine coolant temperatures. Usually the fan will only run when the vehicle is stationary or at low speeds, when air flow across the radiator needs to be increased.
BMW X3 models utilize an electronic cooling fan integrated into the cooling fan shroud. When repairing, the cooling fan and shroud are replaced as a unit. The cooling fan is responsible for maintaining proper engine coolant temperature and A/C cooling. When a BMW X3 cooling fan fails, the fan will not activate or only activate at high speed. You can check cooling fan operation by turning on your air-conditioning and listening for the fan to activate.
When replacing your electronic cooling fan, you will want to work with the engine cold and disconnect the battery's negative cable. Disconnecting the negative battery cable will prevent the electric cooling fan from starting while being serviced. The fan could start at any time and personal injury can occur. Don't skip this step.
For a quick test of the fan, turn on your A/C, the fan should come on. If it does not, it may be faulty. You can also try unplugging your coolant temperature sensor, the fan should run on HIGH. Keep in mind with this technique, a fault code will be set and have to be cleared. Or you will be stuck with a check engine light for a few days until it automatically clears.
Remember your car may have been serviced before and parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.
Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.
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Working in the trunk, disconnect the battery negative cable and cover the battery terminal so the cable does not accidentally come in contact with the terminal. See our tech article on battery replacing for notes on disconnecting and reconnecting the battery.
The fan is mounted to the engine side of the radiator (red arrow).
Start by removing the four T25 Torx fasteners (red arrows) for the fresh air intake duct. Next you will unclip the five air filter housing retaining clips. Lift them up and unhook from the lid of the intake air housing. Start with the two near the mass air flow sensor. Then release the front clips.
Lift the cooling fan straight up (red arrow), push it toward the right of the vehicle, be sure it clears the radiator reservoir. Then pull cooling fan up and remove from engine compartment. Be careful not to snag fan on wires or hoses.
When installing new cooling fan. Slide down into engine compartment, move into place aligning the tabs on the fan (green arrows) with the slots on the radiator support (red arrows). Be sure fan is properly seated in radiator support. If fan is giving you a hard time and will not drop all the way down, check to see if bottom of cooling fan is hung up on radiator or hoses. Reroute wiring harness and connect. Install engine splash shield and check cooling fan operation. You can check operation by running engine and turning on A/C, cooling fan will run when A/C is switched ON.