How often do I change my fuel filters?
 

I changed the oil and put new fuel filters on my 300D when I bought it last spring. I've put about 4000 miles on it now and it is time to change the oil. How often does one change the fuel filters, with the understanding that the car is running well and I am not showing symptoms of clogging?

thanks,

I would keep an eye on the pre-filter if it starts to look dirty change them out. Otherwise I'd say every 3 or 4 oil changes would be fine.

PEH's rule: When they clog up or hell freezes over. Whichever comes first.

Fuel filter longevity in mainly a function of fuel quality, which is neither predictable nor directly within our control. My advice is to let them go until you notice a performance problem. And always carry a spare; it only takes one bad tank of fuel to clog a filter.

I got some bad fuel at a truck stop once. I knew something was wrong when I pulled out of the station. After driving just a few miles, I could not get over 35 mph. The secondary filter was full of a silt-like material.

30 k is what msot people say, with a older benzie stay away from valor biodiesel. youll see little black spots in your line clear filter that is parts of your rubber fuel hose!

I don't change fuel filters until I feel a slight miss on a good up hill grade. Not a good idea with a Cummins tho.

That's what I've always done, until someone here pointed out that the spin-on filter also acts as a water separator. I changed mine a couple of weeks ago, because I didn't like the idea of having some unknown amount of water trapped in the filter, especially in the winter. I might start changing mine every fall, just because.

Yah, thats a thought, although I've never heard of anyone having a problem ingesting water into their engine from the secondary filter. Seems like it could happen, tho.

I change mine every 30K although somehow I thought I heard the standard is 60K.

OK, maybe I'll change the pre-filter when I do the oil next spring. I'll buy the next one now and put it in the trunk or something just in case I need it sooner.

thanks,

When I do a filter change, it is both pre and actual filter. I change BOTH and not one or the other.

no piont changing the clear prefilter unless you can see junk in it. I carry spare fuel filters AND the tools required to change them. Also, I have an unopened qt of tranny fluid or seafoam to prime the secondary filter with if it needs changing. saves a lot of pumping.

An alternative to the sea foam or atf is before removing the filters, remove the return line and let the engine run for a few second and fill up the new secondary filter. Then shut it off, remove the filters and install the new filter that is now filled with diesel.

I do both of mine every fall before I store the car. Usualy about 5k-8k miles on them. They are cheap and I want to keep my car running 100%.

There was a post on here a long time ago where a guy changed the fuel filter on a car that was running badly. He found the disc end of the filter was visibly rusty. :eek:

On mine, I pull the filters and dump the contents into a bowl occasionally. There is always a few drops of water in there, especially in cool weather. I normally replace them at 25k on the 300D and 10K on the 240D. The 240D has some rust in the tank, so I change filters more frequently. I have a fuel filter assembly off a 115 240D (has a drain plug), but have not installed it yet.