Changing the Fuel Filter...

[e34.535i.sport]

Thought i'd give something back to the place i've took so much from... Hope this is some use to someone in the future... I'm only a rookie at the moment but my repetoir of successful car repairs and maintenance jobs is increasing rapidly! I hope some of you other first timers find this helpful...

BENFITS: I found by changing my fuel filter my car idled a little less roughly and the acceleration felt much smoother through the rev range. I'm hoping it will help the fuel economy too... Hoping... (Mine hadn't been changed in a loooonnnnnnngggggggg time!).

MY EXPERIENCE WHEN CHANGING THE FUEL FILTER:

Ok, so i generally buy all my parts from the dealer and try to fit them myself (maybe not the cheapest often but i feel secure with it!), so i have the correct filter for my 535i sport. (I believe the 540i has two!)

The haynes manual recommends depressurising the fuel system before starting and removing the negative battery cable before you get to work on it. I have heard arguments for and against depressurising the system but i decided against it and ran my car low on fuel instead so if there was a leak it wouldn't be much. It worked well. I didn't disconnect the battery either, as i couldn't see a problem arising with any electrical parts (i think it suggests disconnecting the battery because some fuel filters are found in the engine bay - probably a good idea if yours is ).

First things first, remove the driver's side rear wheel and secure the car (on axle stands bla bla bla), and have a look underneath. You'll see it. It is attached to the car via a large round bracket (probably rusty) with a bolt threw the top securing it. Get a ratchet on this and i advise WD40 or something similar. Unfortunately fools rush in (no WD40) and i managed to snap the head off the bolt while it was still in the hole but this wasn't a problem as it releases the filter anyway. It will now be hanging by two hoses... You're getting there don't worry...

Now is the time to get a washing up bowl or something underneath to catch any fuel drippage.

There are two hoses connected to the filter with jubille clips (hoseclamps) one on each. This is where it gets interesting as i am assuming everyone else will encounter the same joyful rusty clips as i did. If your lucky, you may simply be able to untighten the clips using a screwdriver (depending on when it was last changed! But still replace these clips with new ones). If you have luck like mine you'll try the screwdriver on the old clips and the heads will turn to rusty dust. Once i had got to this point i seemed to have two options...

1 - Give up (not really an option for me).
2 - Cut the hoses.

So i went with option 2 using some large scissors - to no avail as the hoses are made out of some very resistent materials. (I was worried about using a knife for some reason...).

Luckily i barely scratched the hoses with the scissors (thinking back not such a good move anyway), so i then got started on secret option 3 - Destroying the jubilee clips (hoseclamps). I got the pliers out of the tool kit and mauled the clips off - which wasn't too hard as they were rusty! Good old secret option 3.

Now the hoseclamps are off its just a matter of disconnecting the filter and changing it. If its your first time its very daunting - i was so nervous i was expecting a blast of fuel to come out and knock me over or something ridiculous like that. In reality i pulled off the hose on the drivers side (it took a bit of force) and a very small amount of fuel trickled out of the hose and filter (aim these into your bowl). Not bad at all spillage-wise. Same with the other hose, and then i put some new hoseclamps on and reconnected the two hoses (tighten them securely) and then had the probelm of the bolt i broke earlier. Securing the round bracket to the frame is normally done with the bolt you see. Well, i don't have the tools or know-how to drill it out so i simply used three cable-ties to secure it. Worked a treat and will certainly be secure enough. (the cable ties you use to stop wheel-trims coming off steel wheels - cheap and very strong!).

Now put the wheel back on, lower the car and start it up. The first time mine cranked but wouldn't start. This is obviously due to the interruption in fuel supply. I depressed the accelerator a few times and then tried again and VROOOOMMMMM!!!!!

Interestingly, i looked at the date on the new filter (2006) - fair enough, made last year and i bought it this year. The one i removed from the car had 1993 on it!!!!!!!! I'm guessing it hadn't been changed in a while!


Good luck first timers... Piece of cake.

[Adnan]

Hi,

I used pinch clamps to shut off both flex lines on the filter. Worked well but it has been a while, perhaps I should change my filter again. I did not disconnect the battery either.

However, running the tank dry can cause the pump to pick up debris and it can also cause the pump to overheat since it derives cooling from the fuel in the tank.

I found that if I positioned the car just right on the edge of my driveway, the overhanging rear allowed plenty of room to crawl under as the driveway sloped away. I didn't have to jack up the car or remove a wheel.

Regards,
Adnan

[e34.535i.sport]

Hi Adnan,

If that method works for you great, but be aware pinching the hoses can have its own risks as well. I find car DIY is quite a personal thing, and you're best doing whatever works for you.

The thread is merely a depiction of the events i encountered whilst changing my fuel filter, i certainly don't imply that it is the only way to do it or even the best way, it is just the method that worked for me.

You are dead right about running dry though, it is not good for a car. I certainly didn't suggest in my post that i was running on fumes, just that i ran the car 'low' on petrol. I know for a fact i had well enough to prevent what you are talking about (which is an extreme case of course). I also know that if i had 3/4 or a full tank of fuel when doing the job there was the potential to lose a lot more if something unexpected happened. Better to be safe than sorry.

I'd make sure you're putting the handbrake on tight when crawling underneath the car on your sloping drive - otherwise things could get messy!

Thanks for the input Adnan.

[Adnan]

Hi,

You are quite correct; pinched hoses can lead to nasty problems. As the car ages, that problem gets worse so I'd better not pinch them this time.

Thanks for the warning!

Regards,
Adnan

[markus]

it makes a nice difference if the PO had them replaced but the idiot mechanic installed them in the wrong direction. The fuel filters had a 1999 on them so he was driving like this for 7 years!

[e34.535i.sport]

it makes a nice difference if the PO had them replaced but the idiot mechanic installed them in the wrong direction. The fuel filters had a 1999 on them so he was driving like this for 7 years!

passenger side right?????

[genphreak]

Sweet. Most people don't change them every 40,000km. A 2 year old filter can make life very hard for the pump and cause failiure. Its always best to have regular maintenance.... Good work with the write-up!

[e34.535i.sport]

Sweet. Most people don't change them every 40,000km. A 2 year old filter can make life very hard for the pump and cause failiure. Its always best to have regular maintenance.... Good work with the write-up!

I'm not sure mine has in the past but its got a good home now!!! Thanks!

[Paul in NZ]

when ever discussing "passenger" or "drivers" side it always pays to remember we have different cars(ie lhd or Rhd)