325i fuel tank fit my 318is?

[e30mitch]

Hello All,

Would anyone know if a gas tank from a 325i will fit my 1991 318is coupe? Mine has a leak somewhere and need to switch it, but cannot find someone who is selling one directly from a 318is. Thanks for your help!

[roguetoaster]

Yes, either will fit, but the larger tanks lack the crossover pipe and instead used a second pump to move fuel from the DS to PS tank. You can add a lift pump or a crossover tube if you really want to, but a smaller tank will be the best option. Remember, don't get tied to the model when it comes to tanks, or other parts, as the fuel tank in your car isn't specific to a 318is.

[bmwman91]

I had looked into this a while back as well, and decided it was too much for the reasons roguetoaster mentioned. Aside from the extra pump, you would need to install the second level sender and swap in the fuel level gauge (in the cluster) for the larger tank. While the extra range would be nice, it is a lot of work!

[pandaboo911]

I was able to install a 325i tank in my 318i, not 318is. Not sure if that's helpful. Only issue was the fuel filter did not fit in the stock location on my car.

[ForcedFirebird]

There is only one pump in a 318is, and only one sender. The tanks physically fit, but the 6 cylinder late model cars used dual fuel level senders (with matching gauge). The return line is at the bottom driver side of the 6cyl tanks, and have a suction tube inside them to move fuel from the driver to passenger side. Early model (the small ones) used the cross over pipe on the bottom and had one side of the tank lower than the other to transfer fuel across the saddles. Both the early model and the 318 tanks use a return on the top of the fuel pump itself. Early models do have two pumps, but they aren't both in-tank, one is a low pressure lift pump (in-tank), the other is an external high pressure pump.

So, ultimately, the tank is a drop-in, but you will have to use a 6cyl driver side sender to cover the hole on that saddle, block the lower return line inlet on the lower driver side of the tank, and use the 318 pump/sender setup.