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Procedure to change gas line filter

I have a 1989 BMW 325i and I believe the gas filter is clogged. When I try to accelarate, the engine wants to “die”. I was told to replace the filter first and then the pickup screen in the tank as a last resort. What do you recommend as a proper procedure to replace the filter—SAFELY! Thanks for your time on this matter.

Frank Baker

Lynchburg, VA

To do this safely, the vehicle needs to be raised and supported safely as the fuel filter is located under the vehicle on the drivers side sub-frame rail. Then a pair of fuel line pinch-off pliers are clamped onto the inlet/outlet hoses of the fuel filter. Then the clamps are loosened from the fuel filter hoses and the filter is removed.


If you’re going to be doing your own maintenance on this car, or any other car, one of the best investments you can make is a service manual. Factory manuals are best, but they’re also the most expensive. Haynes manuals and similar are usually OK for most DIY projects, but they might not be detailed enough for something really serious like an engine rebuild.

Used manuals are available for reasonable prices at and other sources.

I’m sure the first step is “relieve fuel system pressure.”

I recommend the repair manual. You don’t have a repair manual because…?
Here are the instructions, for changing the fuel filter, from If you need instructions for something else, you’ll find that there, also.

Considering the age of the car, if the fuel filter is clogged odds are the pump is failing also.
Even a partially clogged filter on a car that exhibits no performance problems can shorten the life of the fuel pump.

The Bosch pumps used on BMWs, VWs, SAABs, Benz, etc. are high winding pumps and have a tendency to develop some serious commutator wear on the armatures over time.
Worn commutators mean a dragging pump, lower fuel pressure, and eventually buying the farm.

You could try changing the filter first and checking the current draw of the pump. If it’s up in the 10 amps or so range after a filter replacement then the pump is on the way out.

Any idea if your car is a late e-30 or a early e-36? Makes all the difference in the world about filter location and driveability issues. On a late e-30 you could be into the CIS world (a place you do not want to be).

I am thinking e-36 since you say 325i and I can’t remember a e-30 325i (perhaps there was). On a e-36 325i the filter is up front next to the transmission bellhousing.

Why are you emphasising “safely” of course you want to be safe,are you seeing something that makes you feel uneasy about this job?

Thank you so very mjuch for your response to my situation. How do I determine if I have the e-30 or 36? I have located the filter under the rear passenger side in from of the left rear tire. I would like to replace this filter myself because I can not drive the car to a repair shop. It hesitates badly when I press the accelarator and even when I step on the brake peddle or turn the steering wheel. I am somewhat mechanically enclined but when dealing with a combustable material like gasoline, I have found it too late to say “whoops”! Thanks again for your imput and I look forward to your next response.
Frank Baker

By filter location I would say you have a e-30. Check the hood struts (the little shocks that hold the hood up, e-36 will say e-36 on them. By the way does you hood open “backwards”? Memory is terrible but I really believe e-30 hoods open backwards.

The hood opens backwards. No hood struts. Being that I am not an auto buff, what is the difference in the e-30 and 36? Thanks again for your imput.
Frank Baker

The e30 and e36 are mechanically similar but the body styles are quite distinct. e30 was 1984 to 1991 and e36 was 1992 to ~1998. Just Google ‘e30’ and ‘e36’ and you will see images that show these cars.

The best manual to get is Bentley. I got mine on

The general approach for changing a fuel filter is described on my web page:

The biggie for me with the e-30 is its (as I mentioned) use of CIS for fuel injection. Frank you should also “google” CIS injection,don’t believe all the “best injection type known to man” stuff.

I would like you to verify your car uses CIS,does it have a fuel metering head with six hard fuel lines running from it?

I am not saying for sure your car is a dreaded CIS version as I had a e-30 320 (1986) European version 6cyl that was not.