My tank filter was clean as a whistle too yet the prefilter would plug in a day with 'coffee grounds' type of sediment. In addition to Startron I recommend Biobor JF biocide which is what the Army uses but don't overdose the Biobor.

Alex,

That is a great description of exactly what the "rust" looks like when I empty the prefilter and main filter. Truly appreciated.

Biobor works well, BUT it will clog up the strainers until it has all been cleaned out.

Startron kills and dissolves the creatures and the remains will make it through the filters.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

DEcaturJody, beautiful 300D !

Mine is a 1979 non turbo and I find the performance quite adequate for City driving and Highway also.

I agree that having your tank cleaned and treated is probably the best solution.

Some shops can 'boil' if for you and probably treat it as well.

But, if you are handy, it will give you more satisfaction to relish the success !!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

My 79 was a wagon, it had plenty of power for city and highway speeds, but if i had to slow down on highway, regaining speed was difficult. Otherwise it was a dream and i miss it now.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thank you! Agreed on performance. Highway on ramps generally need to be timed because of relatively slow acceleration but once up to speed I have no complaints. My son and I drove to Radwood Austin last year (about 230 miles one-way) and cruised at 80 most of the time. The cruise is not currently working and on my list.

The correct tail light bulbs do affect the cruise control believe it or not!!

Buy the OEM German (European) ones.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

UPDATE! - Thanks to all who weighed in on my trouble with what looked like coffee grounds clogging up my prefilter and main filter. I changed out the prefilter, ran what felt like a tiny amount of bio kleen diesel fuel biocide into the tank, filled it up and made several "spirited" runs. The "coffee grounds" were still in the prefilter but after changing it out again and a few more runs the prefilter is now clear!

Truly grateful for your help.

-Jody

Might as well change the main fuel filter or at least remove and inspect for crud.

Congrats!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

You are right! That is my next step. I had previously purchased an MB main filter and will get to that this weekend. Now where is that extra crush washer...