Midas,

You cannot confuse engine oil in a Diesel with fuel as the engine oil will always be black as coal right after it goes in. The fuel is always going to be pretty clear, a little color now and then depending on what the brand practice is but still always clear. If the fuel is not clear we have a different issue.

Anywhere you see leaks it is a problem. If you have access to a digital camera and can post some pictures you can get some help identifying the parts. I noted before the cloth covered rubber lines that are about 3/16" in diameter that jump from injector to injector, except on the very rear and front of the engine, where the rear one terminates and the front one goes to the filter assembly, are all candidates for routine replacement due to leaks. I think the temp and cyclic pressure pulsing just ruins them quickly. The termination at the rear most injector is also a candidate for early demise.

The other hoses consist of the lines coming from the tank to the injection pump, through the in-line filter (is yours clear and clean? These are about $2.00 and should be checked for crud every year at least.) and the injection pump to the filter assembly. All but the clear one have given me trouble and needed to be replaced. I have yet to replace the clear one. Don't worry about that bubble, I see them there once in a while also, but I do not think that is in the high pressure portion of the system, and it is not leading fuel back to the injection pump so it is ok.

All but the thick black rubber hose that goes off the back of the filter assembly are things you can buy in bulk. The black rubber "Cuban Cigar" hose is a particular part and can be purchased from FastLane I believe, along with the bulk other hoses (the small injector daisy chain, and the larger - maybe 3/8" diameter - fabric covered hose).

Well, thats it for now, Good Luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)