Drain the fuel tank into something clean so as to be able to check for alge. If the old fuel is loaded with "black stuff", I'd recommend that you pull the tank out and thoroughly flush it, then pour in some muriatic acid (be careful!), slosh it around then again thoroughly flush it and dry it. If you don't truly kill the alge, it will haunt you for months to come and it isn't fun. Also, add a bottle or two of algecide to 5 gallons of fresh fuel, then remove the out line from the main fuel filter, hand pump fresh fuel through until it runs clear, then pull both of the in-line filters and change them. Check the small in-line fuel filter once a week for alge.

I bought my first diesel from a LOL that probably filled the tank once every 6 months and the alge was so bad it ate through a fuel line. Good luck.

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles