Hi Everyone,
10. Get a new fuel filter once every 5 years (every 3 years if you drive alot).
For convenience, group this replacement together with other things you'd replace at a similar interval. Buy a new filter now and write the future replacement date on the box to help yourself remember. Display the box on your mantelpiece. lolol When you replace replace it in the car, write the month and year clearly on the filter housing in permanent marker.

You can reference my previous post in the other thread, but here is my take on the subject. Fuel filters are very inexpensive when you take into consideration what you might do to your engine by cleaning it.
I can also eliminate 8 of the 11 steps you take to clean a fuel filter:

1) Buy a new filter for ~$12
2) Install new filter

Also takes quite a bit less time :thumbup:

A fuel filter is like any other filter (air filters, oil filters, even shop vac filters)- not designed for cleaning and reuse. Best bet is to buy a new filter and be done with it.

 

A fuel filter is like any other filter (air filters, oil filters, even shop vac filters)- not designed for cleaning and reuse. Best bet is to buy a new filter and be done with it.

You can go that route if you wish but I see no reason to waste money on things that are not required. Whatever money is saved along the way will be used for the car anyway, will go towards a future repair, paint job, rims, better tyres...there's no limit.

And of course its easier to buy new, but hey, like I said, it only takes 5-10 minutes to wash the filter, and no special skills are needed. I doubt anyone lives their life such that 5-10 minutes saved on a weekend is worth a helluva lot more than $12. It probably takes you at least 10 minutes anyway to drive to the store to get the filter or logon and order it online. The temporal cost benefit analysis is does not reveal any compelling savings by buying new.

And I'll disagree with you on the so called fact that filters are not designed to be reused. This is a myth perpetrated by industry for obvious reasons. What clued me into this was encountering washable, soakable and reusable air and oil filters. After examining the filter material carefully and the net effect of filtration on the engine and fuel system, I came to the conclusion that using new ones all the time wasn't necessary. I had a fuel filter cut up as well and on the inside are the same cellulose vanes that you find on an oil filter.

I buy new cellulose oil filters each time purely because its way way too messy to wash it out. Yes i tried once, for the sake of experimentation. I might consider switching to stainless steel oil filters but I've not found one designed for the e34 as yet.

Btw....knowing that its safe to clean filters in water gives you the ability to wash them out whenever you feel like babying your ride just for the hell of it.

 

buy a new fuel filter. they are inexpensive!

 

If one finds oneself hesitating to spend $60 on a new crank sensor, maybe the cost benefit analysis becomes clearer. And remember, we're not talking about saving the cost of 1 filter, we're talking about saving the cost of 5-10 filters over time. And because of the ability to wash and reuse, you can clean your filters at half the recommended intervals for their replacement, which ultimately contributes to good maintenance.

Anyway, I simply don't believe in spending money when its not necessary, and particularly so when doing so makes me a willing lemming to an industry that relies on exploiting the uneducated. Just look at all the fuel injector cleaners being sold out there and you realise how stupid people can be and how many billions are being made from them every year for the past 50 years, the process of which simply perpetuates the misrepresentation in question. Not for me.

 

I think everyone can appreciate saving a few bucks, however I also appreciate the peace of mind a new filter instills. It is nice to see the "good" you are doing when you see brown and black crud coming from your fuel filter (and also doing an oil change- all the crappy black oil drains out, and you pour in that golden oil from the top). But how do you know what is left behind in the filter? There is a saying, "There is more where that came from". It is impossible to get all the contaminants out of a filter. That is what a filter is designed to do- trap contaminants, and keep them trapped so they do not re-enter the system they are filtering, whether it is oil or fuel.

 

Goosefoot, it was ultimately the black and brown crud flowing out the fuel filter that spurred me to start washing it out rather than changing it. The damn filter is merely functioning as a physical TRAP to particles. IE there's no chemical neutralisation going on similar to say what happens in a catalytic convertor. And this is sufficient for the engine's good performance ! This was news to me.

Anyway, as i said in my op, replace your fuel filter once every 5 years. I've not done this for more than a few months so I'll put in that caveat just in case I'm wrong for some reason.

Observe the crud that comes out carefully, cut up a fuel filter and look at it, and see what occurs to you. And do lots and lots of reading on the internet for filtration ratings. Consider the tons of high flowing sports air filter companies who've been in business for decades without being screwed by lawsuits. Think about filtration as a concept and how it works in tandem with the rest of the engine, fuel system, etc. You'll eventually come to the same conclusions that I did.

Of course, peace of mind is peace of mind. There's no substitute for it. That's why I recommend reading up on all of this to enhance your base knowledge...knowing how things work will give you that peace of mind sir.

Consider something else. I've been on bimmerfest for awhile now. I've read about more than one instance of low, sporadic or no fuel delivery situations at the injectors, which were ultimately solved by changing the fuel filter...not the injectors. A clean fuel filter is probably all that you need to keep the injectors clean or at least clean enough. I run diesel treatment through my tank once every 3 months but i've never noticed any improvement as a result, but i don't mind being anal when its so cheap and convenient with no danger to the car in any way.

(As an aside) I'd still suggest removing the injectors and backflushing them at least once every 5 years for the heck of it (in conjuction with regular diesel treatments in the fuel tank and regular rinsing of the fuel filter) but its probably in the overkill category. Half a year ago, I replaced my whole set of injectors with a remanufactured set kindly contributed by a fellow fester. One of my existing injectors was clearly not firing enough fuel when the rail was held up and the car was cranked. My car had not thrown any injector codes. The other injectors were fine, but it seemed logical to assume that if one was screwed, the others were not far behind ? I installed the second set of injectors and drove my car.

The effect? Zero. The car felt and behaved exactly the same. I'm still glad I got remanned injectors in there, but it highlighted the fact that the car's fuel delivery system in general and injectors is particular are not as fragile as all those rows and rows of fuel injector cleaners on store shelves would have you believe.

rgds,
Roberto

 

On my same search of "How to clean fuel filter", I ran into more articles showing the steps to "Replacing an old fuel filter with a clean new one" than the initial search. I also found a short and concise note on eHow, by far the simplest DIY site currently on the intarweb:

Fuel filters are one of the most important yet most affordable parts of a car to replace

Read more: How to Clean a Fuel Filter | eHow.com http://www.ehow.com/how_5117221_clean-fuel-filter.html#ixzz1DoCFbojw

 

That's a good link. However, the method it describes is an overkill and treat the filter as made of fragile material which it isn't....its not made of some highly sensitive material installed in a clean-room environment. So you don't need to go through all those complicated steps which are very time consuming, in which case of course it would be smarter to buy a new filter.

Yes, carburetor cleaner (that's essentially what b-12 chemtool is) would be nice, but its not necessary if you use regular diesel treatments in your car - this dissolves varnish and smaller particles in the fuel system including the filter. Even if you spray that in (what the hell should be alright) you can drip dry and reinstall immediately. They are using illogical assumptions (when you pause to think about it), by asking you to stand the filter for an hour after using the carb cleaner on it. Carb cleaner is combustible and compatible with fuel. I've sprayed carb cleaner into my throttle body with the engine running, and into my fuel tank directly as well. No problems for the car. So why take 1 hour to let it all evaporate away?

The article's author is using theory without practical experience to construct his method. Of course what he says works perfectly but it takes so long and is thus inefficient especially when considering that the fuel filter is relatively cheap. I've found that its a good idea to apply ecology tests to what you read on the internet or hear from mechs. Helps eliminate the crap or refine the good stuff down to its key essentials.

 

I would rather spend $15 on a new filter and have a car ready to go after five minutes instead of making it a hour or so job. Just my personal opinion which might be wrong but it is what I think.... In my experience introducing any kind of water to the fuel system seems totally bass ackwards.

 

Why would anyone spend an hour in order to save just $15? Please read the instructions in my original post in this thread. Washing the filter with water takes 10 minutes or less. Do it once with an old filter and you'll see why. You can take 1 or 2 hours if you like but you won't be getting any additional benefit or avoiding any particular risk, which i stated there as well.

And as to introducing water into the engine, please google 'water injection' and 'water decarbonisation.' You'll find lots of information about water in engines and you'll realise that its not what you've always assumed it to be.

This is part of the reason why I realised that cleaning out fuel filters in water works. I looked into those topics when i was checking out turbo and in-car combustion chamber cleaning. When you read widely, you tend to correlate information that you encounter about one subject with something else, if it applies.

 

I see the point of reusing the filter. I defiantly thought that if need be, the last dirty filter could be cleaned as most of the particals washed out on removel. When cleaning pools, the filters pressure built up over the mths accumulating debris.the remedy was to back wash the filter removing trapped particles redirected away. This would reduce the back pressure.And increase the suction. As long as you had filter integrity .The pool would stay crystal clear. In relation to the thread i don't see why one could not effectively clean any filter given a proper technique and cleaner. As long as you are getting 45 psi at the injector rail. $20 saved is $20 earned.

 

Backflushing is definitely required when we're dealing with small diameter applications such as fuel injectors. However, the fuel filter does not filter down to that level...its only made of cellulose, which, when magnified, reveals huge spaces between the fibres. So simple washing out will do, but i guess its a good idea to use carb cleaner on the front and back (3 second spray each time), then shaken about gently for 60 seconds, then poured out. This should only be done after water runs clear following the cycle listed in my op. After the cab cleaning, a final rinse and shake in water before reinstallation.

Carb cleaner can be replaced with ethanol.

I don't really know if this will help much, i don't really think so, but it won't hurt and since its on ehow perhaps its worth adding to the list above as an optional step.

And yes, money saved is money earned.....but its only earned to pay for something else towards the car...that has been my experience.

 

You do it your way and I will continue to do it my way. Whether my way is the right way or not I am still going to do it like that.

 

Keep that up and I'll send you to your room ! lolol

Dude, its your money, time, belief systems and car. Do as you please, but do it (i.e. replace the fuel filter in your case) at least once every 30k miles, and group it with other 30k interval work for convenience and to ensure that you don't forget it. Cheers.

 

Good show Roberto. There are a lot of hacks outside the box....you just have to let your mind come out and do your thinking out of the (commerce) box. Deciding whether to clean or replace is a function of money and convenience. A cheap fuel filter does not hurt to replace, but when you have a 90 dollar fuel filter (MB ML320) your attention naturally drifts into finding ways to clean it. I just replaced the fuel filter on my 740iL, but after reading this post, I will dig out the old one and clean it up as I recall that the gas that came out of it was rather clean. My MB ML320 SUV has a lot of water and debris in the fuel tank, so I was preparing to remove the fuel pump for access, empty the tank, dry it with a leaf blower and remove the dirt with a vacuum after it is completely dry. I wandered into the internet looking for options on the filter and this is how I landed on this thread. I will definitely give it a try before shelling out the 90 dollars plus tax that a new filter cost. Thanks for your contribution.

 

It was good to reread this old thread.

Roberto made a few errors :

a. It takes 1 second at key2 and not 30, to repressurise the fuel rail.
b. Backflushing fuel injectors is not an overkill (he said it probably is).
c. Injectors should be backflushed not less than once every 2 years, and not more once every 5 years as he mentioned.

I'd like everyone to look at this excellent video :

https://youtu.be/92TfTQTmuq4?t=8m56s

The video is ten minutes and well worth watching. In the link above, I've advanced the video to a timestamped portion because it shows you how much and how little a fuel filter can actually do to dirty fuel in that section. Please watch only that portion if you don't have time, but if possible please watch everything.

The importance of keeping a fuel filter at a high baseline for cleanliness has been well established by that section of the video. Though a filter rated for 75k (for example) still filters fuel well enough at 74k to be used, I'd rather keep it at a 30k level of cleanliness, all the way up to 150k.

Especially if you have a new / very low miles fuel filter, please rinse it in water every 30k. Excluding removal and installation, it is a 5 minute process.

cap

p.s. Smoothops, Roberto says gracias.