The BMW 3 Series has gone through five generations since its inception in 1975. The windshield-washer reservoir holds the solvent that is pumped through the washer system and sprays onto the windshield, helping the wiper blades clean the windshield of rain, debris, and other obstructions. The windshield-washer reservoir sits in the engine compartment on the passenger side. However, the easiest way to reach it is through the passenger-side wheel well. If your reservoir leaks or has been damaged in an auto accident, removing it is a straightforward process, although getting the tank off the car requires an extension socket wrench, since the bolts are very difficult to reach by hand. However, with this tool you can finish the job in an hour.
Crouch next to the front-passenger wheel well and notice the bolts holding the front inner-bumper well to the BMW. Remove these bolts with the socket wrench and tuck the bumper well out of the way.
Pull back the inner bumper slightly and notice the large white tank with a black cylinder attached to it. These are the windshield-washer reservoir and washer pump, respectively.
Detach the power cable from the pump by depressing the tabs on either end of the plug and pulling it off the socket. Pull the delivery hose off the pump nipple opposite the power socket.
Shine the light of a flashlight into the cavity housing the reservoir and note the two hard-to-reach bolts securing the reservoir.
Remove the two bolts securing the reservoir using the socket wrench with an extension, turning left to loosen.
Gently pull the reservoir out of the cavity by pulling it toward yourself and rocking it to the left and right to work it out of the cavity and past the inner bumper.