Project E36 M3 - Changing the Fuel Filter September 21 2013
If your car is down on power or sputters when starting, this may be a sign of low fuel pressure. That could mean a leaky injector, a failing pump or a dirty fuel filter. Since the filter is so cheap and easy to replace, it's usually the first thing to try. The fuel filter removes the dirt that would otherwise make its way down the fuel system where it can clog injectors or accelerate wear in your engine. If the fuel filter gets too clogged with contaminants, fuel has a hard time getting through, and you may have reduced fuel pressure at the engine. This means your engine will be running lean and not getting all the fuel it needs. Our E36 M3 didn't experience any of those symptoms, but it has been about 40,000 miles since the last fuel filter change, so it was time to swap it out with a new one. Before we started this job, we ran the gas tank down to nearly empty in case we sprang a leak that we couldn't stop. We also moved the car out of the garage. It's bad if your car catches on fire, but it is worse if your garage goes up in flames too. Good ventilation is important too, since there is going to be spilled fuel. As a good measure, we removed the fuse to the fuel pump and ran the engine until it died to bleed fuel pressure from the system.
The fuel filter is located approximately under the driver's seat for late model 6-cylinder E36's. You'll need to get the car up in the air to access it. I lifted the left hand side of the car only. Disconnect the battery and get your fire extinguisher out, since there is going to be some fuel spillage. It is unavoidable. I'd also recommend safety glasses with good wrap around protection. If you're under the car and looking up, dirt and fuel is going to get in your eyes otherwise.
The light-grey cylinder in the center of the photo is the fuel filter. There is a cover that needs to come off to access it. Remove the four bolts and move it out of the way.
With the cover off, we now have good access to the fuel filter.
There is a saddle clamp that secures the fuel filter. Remove the one nut that holds it on. It's hard to see the nut in this photo, but the wrench in the photo is turning it. Once the nut is off, the clamp will loosen, but because there are a bunch of other lines attached to the clamp, it doesn't swing out of the way completely. When it is time to remove the fuel filter, we'll have to gently tug on it to open up further.
Loosen the hose clamps on the lines going to the fuel filter and slowly work the lines off. I used a flat head screwdriver and a prying motion to push the hose off the end of the fuel filter. Tugging slightly on the hose while prying with the screwdriver helps. Another trick is to use an open end wrench of the appropriate size to pry the hose off. Since it pushes on opposite sides of the hose, it works better than a screwdriver, but you have to back the hose off enough to get the wrench in there. The fuel is under pressure and will spray out at you. remove the hoses slowly and don't get directly under the fuel filter. The aft hose doesn't leak much, but the forward one does. I used a vise grip to gently hold the forward hose closed. I wiggled the fuel filter aft to remove it. I worked slowly, pushing some of the other lines out of the way and working the fuel filter aft.
The fuel filter is now removed. Wiggle the new one into place, paying attention to which way the filter should be facing. There should be an arrow on the filter indicating which direction the flow should be going. You want this arrow pointing towards the engine. if you know how to take everything apart, you should know how to button everything back up.
When you have everything reinstalled and you go to start the car, it will take longer than usual to start your car. The fuel pump needs to build pressure back up and needs to fill up the fuel filter and fuel lines before fuel will reach the engine. Our M3 started up after about 5 seconds of cranking.
It's not a difficult job to perform, and your E36 will thank you for it. Stay up to date with all the articles posted here by "liking" us on Facebook and you'll get status updates on new articles. If you love motoring, stop by our online store to check out our line of apparel for automotive enthusiasts.