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One of the basic maintenance projects that you should perform on your BMW is
the replacement of the fuel filter. I recommend that you replace your
fuel filter about once a year, or ever 10,000 miles. It seems that
with today's fuels, there always seems to be some gas station that has
problems with dirt or grime in the gasoline that can clog your tank. I
don't think quality control with gasoline stations is really what it used to
be. Needless to say, I try to replace all the fuel filters at least
once a year.
Changing the fuel filter is not a job that I relish. There is an
almost guarantee that you will spill at least some fuel on the ground and
yourself as you swap out the fuel filter. Perform the replacement in a
well-ventilated area. That means outdoors or in your garage with a few
large fans blowing air both in and out. Have a fire extinguisher
handy, wear rubber gloves, eye protection, and have a few rolls of paper
The fuel tank
should be as low as possible - drive around the car until the gas tank is
almost empty. This will minimize problems if something should happen
to go wrong.
The first step is
to jack the car up. See our
Pelican Technical Article on
Jacking Up for more information. I recommend that you only jack up
the front of the car, and leave the rear on the ground. This will
minimize any fuel flowing forward to the front of the car from the tank.
The E36 3-Series BMWs have a semi-intelligent design when it comes to fuel
flow. The fuel pump is located in the top of the tank, and pumps fuel
out the top as well. Why is this good? Well, when you go to
change the fuel filter, you can pull out the fuel pump relay, crank the car
a few times, and be assured that fuel isn't going to flow everywhere if you
make a mistake. Some cars have a gravity-fed system that takes fuel
out of the bottom of the tank. With these systems, you have to
disconnect the line, and clamp it very quickly, otherwise, the entire tank
of gas will empty out!
Now, pull out the
fuse for the fuel pump (Figure 1), and crank the engine a few times. In general,
this is fuse #9 on the E30 cars, and fuse #18 on the E36 cars - check your
individual model first, prior to pulling the fuse. Removing this fuse
and turning over the car will help to reduce some of the fuel in the system.
Unfortunately, you can't get most of it out, and some will spill when you
disconnect the fuel filter. In addition, the filter itself will be
full of fuel too.
underneath the car. The fuel filter is generally in the same location
for all of the cars - located on the left side of the car, somewhat
underneath the engine (Figure 2,
Figure 3, and
Figure 4). Also see
Figure 5 for a photo of what a brand new fuel filter should look like.
You now want to disconnect the line. I typically like to clamp the
fuel line before disconnecting it as this will minimize the amount of fuel
that will leak out. However, you have to be very careful clamping the
line, otherwise you may damage it. A large c-clamp works well, or you
can use Vice-Grips, but only if you cover the jaws with several layers of
duct tape - this will minimize the amount of damage you will do to the line.
It's okay to squeeze the line closed tight, but you don't want to score,
rip, or crack it with your clamping tools.
With both the
inlet and the outlet to the fuel filter clamped, release the hose clamps on
either side. Have a small pail or bucket handy to catch the excess
fuel when you release the line. Sometimes the line will slip off, but
some times it will require some coaxing. I recommend using a small
crescent wrench that fits nicely around the fuel pump inlet, but is too
small to fit around the fuel line. Wedge the wrench against the filter
housing, and you should be able to pry off any stubborn fuel line. If
all fails, and you simply cannot pull the line off of the filter, then make
a small 1/4" cut along the length of the line and try again. Continue
making cuts until you can remove the line. This will minimize the
amount of line that you will have to cut in order to get the filter off.
When the line is
released, expect quite a few ounces of gasoline to be coming your way.
Be prepared (gloves, eye protection, paper towels, bucket, and a
well-ventilated area). Take the filter out (it's held in with a hose
clamp), put it in your bucket and take it, and any left over or spilled
gasoline outside of your garage immediately. Let the garage sit empty
for about 15-20 minutes before you re-enter - it will take about that long
for the fumes to clear. Then, simply reattach the new filter in place
of the old one. Tighten the clamps tight, but don't clamp them so
tightly that you strip the clamps.
Well, there you have it - it's
really not too difficult at all. If you would like to see
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