How often do you change fuel prefilter and main filter?

[airfoill]

I was wondering how often everybody in the group changes their prefilter and main fuel filter. I bought a 82 240D in August and have changed the pre filters twice (every 3,000) and the main fuel filter once (didn't know when main filter was last changed by the previous owner) since I bought the car. The prefilter is transparent and catches alot of trash before it gets into the main fuel filter. When I visually start seeing that trash accumulate, I install a new prefilter...besides, they are pretty cheap.

Anyway, I would suspect that the prefilter gets changed alot more often than the main filter. What mileage interval do you all use for pre and main fuel filters?

[SW]

I think the main filter is supposed to be changed every 15,000 miles. I replace the inline filter whenever it starts to look clogged.

[MBenzNL]

I know mine is not a 240D, but I change the prefilter and main fuel filter of my C250D every 50.000km (30.000 miles) and never more often...

By the way: did you know there is a (fuel) filter at the outlet of the tank as well?

greetingz,

[airfoill]

Originally posted by MBenz
I know mine is not a 240D, but I change the prefilter and main fuel filter of my C250D every 50.000km (30.000 miles) and never more often...

By the way: did you know there is a (fuel) filter at the outlet of the tank as well?

greetingz,

Are we supposed to change the tank filter at certain mileage intervals also?

[TN-W124 Diesel]

Is this true on a 1983 300d also? Where is it located?

[JoeMB]

I successfully changed both filters in my 1984 300D Turbo, but was unable to remove an air bubble at the top of the pre-filter. I used the fuel system pump device and bled the fuel system but the air bubble remains. The car appears to run fine.

Has anyone else had a similar experience?

[rickjordan]

The "filter" in the tank, I was told, is actually just a screen. However you do have to drain the tank to clean it out. If you think about it, the pre-filter is really just a cone shaped, fine mesh screen it'self. There really isn't any real filtering element like there is in the main filter. When I bought my car, my mechanic recommended changing this tank "filter" when you change out the other filters. He also said very few people know of this filter and often it goes unchanged. To be honest, I haven't cleaned this tank filter, just the 2 under the hood. I would imagine that if your car starts starving for fuel and your pre-filter is clean then the one in the tank should be checked out.

[MBenzNL]

Like Rick already stated it is just a screen and it only needs to be cleaned up when the car is starving for fuel...

This screen is located inside the tank where the fuel hose is attached to the tank. This filter will keep the bigger dirt parts out of the hosing system to prevent them from getting filled up.
It can only be changed when the tank is completely empty (otherwise you will get a real mess...) and it needs only be changed when the fuel hardly gets to the front of the car.
It is used at almost all the benz models.

JoeMB,
an air bubble in the top of the pre-filter is no problem. If it is in the top it can not even get out and if it would get out, you will not even notice it.

greetingz,

Waiting for fuel starvation is one way to manage this problem. I removed mine recently as a proactive measure. In preparation, I ran two tanks of Biobore to kill any microbes and then ran the tank down low. It is really very easy and better than getting stuck on a road trip. I would recommend every 2-3 years or about 50,000 miles, but this is just a guess based on the many cars that go years without problems.

[CJ]

I have heard good stuff about Biobore, but I can not seem to find it anywhere.

The Haynes manual says 30,000 miles. I have changed mine on 25,000 mile intervals with great success. I would recommend carrying a spare set in case the time comes that you get a nasty tank of fuel.

Good luck,

[jylee]

The pre filter is cheap, less than $2.00 each. I change it every time I change oil at 3000 miles. the main filter cost a little more. I change it every 2 years. I put on about 10,000 miles per year.

jack

[Tref]

I was looking for Biobor also and was unable to find it. Then I was in a marina and saw it on the shelf. They have a nice selction of other diesel products there too. Check your local marina.

I actually have fuel leaking from my fuel line so I was going to replace it today. But I think it would be a good idea to clean this tank filter at the same time... will I be able to see it from underneath the car when I pull the fuel line or is there additional items I need to remove to get to it? About how big is it?

Thanks,

SB

Yes, it is on the bottom of the tank and takes a big allen wrench to remove. I do not remember the size. I actually used the head of a bolt and then tightened to nuts against each other and then wrenched on the nuts to remove the screen. This is like a home made allen wrench. Good luck.