Leaking Fuel

kc66

My 1991 E30 BMW is leaking fuel underneath. It is dripping slowly but can be seen on the ground after a few hours parked. There are two small patches beside each other just inside the rear right wheel and towards the front a few inches. I know I need to get this fixed asap but has anyone any idea if its much of a job?

C_Breeze

fuel filter - 25 euro approx

-maybe just needs to be tightened

Litcagral

C_Breeze wrote:

fuel filter - 25 euro approx

-maybe just needs to be tightened

That wouldn't cause a leak at the rear ??? Sounds more like a leak on the pipe feeding the fuel filling point to the tank.

mike65

Sounds like the union joints need a spanner. Have a good look with a torch to see if there is any obvious sign of wear.

The fuel filter on a e30 is proberly at the back (?)

Mike.

JohnCleary

Litcagral wrote:

That wouldn't cause a leak at the rear ??? Sounds more like a leak on the pipe feeding the fuel filling point to the tank.

I'm not sure if fuel lines are repairable.. I would replace such an important part of your car as leaking petrol is a recipe for disaster

mike65

or is this it



Mike.

fletch

Litcagral wrote:

That wouldn't cause a leak at the rear ??? Sounds more like a leak on the pipe feeding the fuel filling point to the tank.

Some fuel filters on cars are at the rear under the bumper....(petrol goes in ere so no reason for it not to be located here)

AMurphy

the first photo looks the part.
Al Bosch filters that I have seen have screw on terminations, not push on.
However, Charcoal and vent fumes filters have had push-on + clip terminations.

Filters tend to have small diameter ~¼" id pipes connected to them, Fume filters have large diameter pipes ~½" ID.

Anyway, for the originator, turn onthe car and you will probably see a lot more fuel excaping, due to the pump pressure, so easier to identify the location of the leak. If it is a blown pipe, you can get fuel line from BMW in lengths and cut what you need, or at least I did when required.

Dilbert75

Late 80's / early 90's Opels had an issue with degradation of the fuel lines in the engine bay. There's a solid pipe from the tank to the bulkhead and then flexible lines from there on. Had to replace the lines on two Kadetts. Same symptoms as your BMW. Just got new fuel line from a motor factors.

stratos

This happened to me. Under the rear seat is opening to the fuel tank.
The pump and sender float are installed in this position.
A gasket provides the seal between the tank and the flange which is bolted in place.
this gasket flange failed on my bmw which allowed fuel to leak out under the floor.
especially noticeable just after refueling.
A new gasket and I was away.

kc66

I can sometimes smell the fuel in the car, only sometimes. But only when not moving after driving for a bit. Thanks for the advice. Thought I might need some major investment.

A gasket provides the seal between the tank and the flange which is bolted in place.
this gasket flange failed on my bmw which allowed fuel to leak out under the floor.
especially noticeable just after refueling.

Its the same just after refuelling as any other time though.

AMurphy

I repaired a fuel leak on an old BMW 535 some time back, the leak as it turned out was through the body of one of the injectors, which was tucked away inside the looped over air intake. Simple fix, but required major disassembly to get at.
Given the difficulty to get at, I serviced them all while I have the intake off, otherwise a fairly simple job.