How to Remove the Radiator on a 1998 BMW E39

1. Lift the front of the car with a floor jack and support the front on a pair of jack stands. Locate the drain plug for the radiator. Open the plug with a wrench and drain the coolant into a container.
2. Loosen the nut on the end of the fan clutch, but do not remove it. This is a reverse thread, 32 mm nut. To prevent the fan from turning while the nut is loosened, wedge a screwdriver between the nut on the water pump and the fan clutch nut.
3. Remove the clip that holds the coolant reservoir in place. Disconnect the overflow hose where it connects to the reservoir by loosening the hose clamp. Pull the hose off.
4. Remove the fan shroud, fan clutch and fan simultaneously. The whole assembly will release from the clips that hold it in place when you pull on it. Disconnect the heater hose from where it goes into the reservoir by loosening the hose clamp and pulling the heater hose off. Remove the reservoir from the engine bay. Loosen the hose clamps that hold the upper and lower radiator hoses on and disconnect the hoses from the radiator.
5. Remove the 8 mm bolts that fasten the radiator clips to the engine bay. There are two bolts, one for each clip on each side of the radiator. Do not lose the two rubber inserts (for isolating the radiator) that slide into the clips.
6. Unscrew and remove the temperature sender on the radiator with a wrench. If you are installing a new radiator, remove the two rubber bushings on the bottom of the radiator and transfer them to the new radiator.
7. Installation of the new radiator or reinstallation of the old one is the opposite of removal. Bolt the two clips on the radiator back into the engine bay, ensuring that the rubber inserts are in place.
8. Reinstall the temperature sender with a wrench. Reinstall the reservoir and the radiator shroud/fan clutch assembly. Make sure that the fan shroud is resting properly on the clips that hold it in place. Install the fan clutch nut by threading it on counterclockwise and tightening it with the ratchet and socket.