The following article gives detailed instructions on replacing the electric cooling fan in an E90 3 series car. Even though we have used a 2011 BMW 335i to perform this repair, this article can be applied to any E90, E91 or E92 vehicle including the 325i, 328i and 330i with minor modifications.
A BMW E90 cooling fan replacement may be necessary if it is not turning on when the radiator temperature exceeds normal operating levels.
One of the most common failure points on aging BMW’s is the cooling system. It is especially noticeable on higher mileage cars, or vehicles that have sustained a front end impact somewhere along their lifespan. As BMW quickly makes its transition from belt driven accessories to “non belt driven” electric versions (water pump, power steering pump and engine cooling fan), changing out defective parts has become quicker and easier to accomplish.
The BMW E90 cooling fan’s main function is to move air through the radiator when the vehicle is stationary or moving at slow speeds. In older 3 series model cars (like the E46), this was accomplished with a belt driven fan on a “thermo” activated clutch hub. When the radiator’s temperature rose above normal operating levels the clutch hub would engage allowing the fan blade to spin. This would cool the fluid in the radiator back down to an acceptable level.
With the introduction of the E90 3 series in 2006 came a new electric cooling fan that replaced the older manual version. The electric cooling fan is a much more efficient mechanism than the outdated belt driven version. It is controlled by a sensor in the radiator that notifies the engine management system (the DME) when the coolant temperature is too high. The DME activates the electric cooling fan which will run until temperatures fall back to an acceptable level.
A tell tale sign that the motor in your electric cooling fan may have failed is if it does not come on when the vehicle is stationary, the engine is hot, and the coolant temperature sensor has been been verified as operating correctly. If you have determined your BMW E90 cooling fan has failed, it must be replaced immediately to avoid overheating and possible catastrophic damage to your engine. The good news is it’s a relatively simple repair that can save the home mechanic a lot of money by avoiding the repair shop.
If you are replacing a BMW E90 cooling fan that has become inoperative, always start by checking the fuse box first to make sure the fan’s fuse has not blown. The engine cooling fan fuse location on a BMW E90/91/92 is in glove compartment fuse box – fuse #F69 (#F92 on post 2007 vehicles) – 50amp.
1. Cooling fan (required) – Always purchase a quality replacement fan from a trusted parts supplier. Cheap “aftermarket” units are known to fail causing catastrophic damage to your vehicle.
2. Coolant/Anti-freeze (optional) – Now is a great time to check your engine coolant and top it off if necessary. It is always a good idea to keep a gallon of Genuine BMW Coolant/Anti-freeze in your garage in case you ever need it. Remember that Genuine BMW coolant must be mixed 50/50 with distilled water only.
- If your vehicle has an automatic transmission, you will need to jack and support your vehicle using the “four corner method”. Jacking E90s with an automatic transmission is necessary since the vehicles ATF (automatic transmission fluid) cooler is attached to the bottom of the engine cooling fan. Please click here to learn how to properly jack and support your vehicle for this repair.
- Remove the front protective plastic belly pan from the underside of your vehicle. It is held in place with 8mm screws.
- With the belly pan removed, locate the ATF cooler attached to the bottom of the engine cooling fan. It is held in place with one T25 torx screw. Remove the screw using and gently push ATF cooler out of the way.
- With the ATF cooler disconnected, move to the engine compartment to finish the repair. First, the air intake duct must be removed. Start at the air box by prying loose the two plastic snap clips with a flat blade screwdriver.
- Next remove the two screws that anchor the air duct to the front grill. There is a screw on either side of the duct.
- Grab the air intake duct and pull loose from the air box.
- Unhook the radiator fluid reservoir overflow line from fan shroud and carefully move out of the way. WE STRESS carefully…the line is connected to the upper radiator hose via a plastic fitting that is prone to breaking. We suggest tucking the line behind the oil filter with a rag as shown below.
- The final step is to unclip the cooling fan from the fan shroud. The mounting clip is located on the left side of the cooling fan, down near the radiator hoses. Pull the clip forward (towards fire wall) to release. While pulling clip forward, use your other hand to pull the cooling fan out of the fan shroud.
Install the new BMW E90 engine cooling fan using the steps above in reverse. Be patient…the fan will not just slide in “nice and easy”…there are radiator hoses and other parts that are going to be in the way. Work slowly and methodically…NEVER force the fan down out of frustration. One usual hangup is the new fan will get caught on the bottom of the radiator. The fan should slide down cleanly past the radiator and lock neatly into place.