BMW E28 fuel tank and fuel gauge
Why does the E28 fuel gauge read too low?
The tank is 70 litres in all E28 models. If the gauge shows clearly less after a full tank, the cause is often the sender: the float may be stuck or the connector rusted. The gauge needle may also have shifted or the lamp socket oxidised.
How do you remove the E28 tank sender unit?
The pump is under the car, not in the tank. The sender unit is reached through the boot via the access hatch on top of the tank. The cover is turned about a centimetre counterclockwise using two flat-blade screwdrivers. Do not pull on the hose ends, as they break easily.
Why does the E28 fuel tank leak?
The tank seam rusts, often from the inside, when the tank has been nearly empty and damp for a long time. The leak can also come from the base of the filler neck or from rusted vent pipes. When replacing the tank, a seized bolt can break off the tank's mounting lug.