Someone previously said the interval change for the fuel filter was in the manual, but I didn't see it anywhere. I think it's supposed to be changed every 12,000 miles? I know the smaller pre-filters get changed on a visual basis, whenever they get dirty.

Also the air filter. A local place said unless you're driving on dusty back roads, which we're not, here in metro Atlanta, once every 30,000 miles should be fine. I don't think he was far off the mark, as a visual inspection shows the filter still looking practically new, and I think it's 3 years old with probably 30k on it.

Thanks,

jeff 1991 300d, 157k

If you're not gonna ADD any Fuel Filtration capability...
I'd do the Secondary every 10K miles.
The Factory Secondary MAY filter down to 10 Microns NOMINAL.

(I'm using a Racor 3203 as my Secondary, which filters down to 2 Microns.)


According to the FSM the Factory Mercedes Air Filter (For the engine) can be
GENTLY, REVERSE "Blown Out" with air pressure.
[NOT 150 PSI !!!] (I'd not try anything over 1 Bar/14.999999 PSI)

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'84 300SD sold
124.128

I only did it when needed - but I always had spares in the trunk.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

Every 2 or 3 oil changes and before a long trip or if I'm expecting long hills. I also keep 2 sets in the trunk.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Fuel filters-as needed, or whenever I just feel like changing them. I've done the fuel filters in my '83 twice in 6 years, but I only drove 18k miles in that time. My '77 picked up a fuel contamination issue while I was away on deployment once, and I must have changed the fuel filters on that thing four times or more in 24,000 miles.

Air filters I just inspect occasionally and change when they get looking bad. I used to work at Firestone on Howell Mill in Atlanta and I noticed LOTS of dirty air filters compared to the shop in Mississippi where I worked previously.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

If you add 1 oz of Startron at each fillup, the interval becomes much longer.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

Fuel Filter life depends on the quality of the Fuel. One load of bad Fuel can plug a new filter up in a matter of minutes.
Next worst is if something is growing inside of your Fuel tank.

So if you are buying most of your Fuel the same place that you know has clean Fuel you might be able to go years with out changing the Filters.

Keeping the Tank Full of Fuel does a lot to avoid water condensation in the Fuel Tank and also helps you avoid having to buy Fuel from a station you have never used before because you are nearly out of Fuel.

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84 300D, 82 Volvo 244Gl Diesel

The specified interval is in your maintenance booklet, p. 88. Air and fuel filters are once every 30,000 miles. But, like others, I think "when needed" is a perfectly valid approach.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

On my 83 300SD, I changed both fuel filters and air filter @ 10K mile intervals.

On my 99 E300TD, I change both fuel filters and air filter @ 20K mile intervals.

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'06 E320 CDI
'17 Corvette Stingray Vert

Actually for about the cost of one secondary filter you can install a fuel pressure gauge in the base circuit of the injection pump. When pressure falls to a predetermined point the filter is offering too much restriction. Or there is something else going on.

Those that do not change their fuel filters often enough or only when they totally obstruct. Especially on the 616 engines may live to really regret it.

There is still no proof of any type but it may impact failure of the first rod bearing or contribute to it. Even if this turns out not to be true low fuel pressure will hurt your fuel milage and power somewhat.