On two occasions, I parked facing up on a friends hill (one month apart) and when I went to start the car (98 E300D) cranked but wouldn't start. I took off the fuel filter and it was half full so I filled it with diesel and the car started after cranking a bit.

I figure that the fuel drained back out of the filter, but there are no fuel leaks anywhere. This never happens when I park in my own driveway which is flat.

Is there a check valve or some other thing I should check. I know I can avoid the problem by parking front down hill, but would like to solve it correctly. I searched but couldn't find any clues.

Hope someone out there can help.

__________________
1991 300D 172,000 (totaled)
1998 E300 Turbodiesel 82,500

You must have an air leak somewhere allowing the fuel to drain back to the tank when pointed uphill. Until the air leak becomes a fuel leak, I'm not sure how to find it.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That is what I thought, an air leak "up stream" of the fuel filter, but I thought if air leaked in, surely diesel would be leaking out????

__________________
1991 300D 172,000 (totaled)
1998 E300 Turbodiesel 82,500

Any chance that your fuel tank was low? and all the fuel just went towards the back of the tank

No, the tank was at least 3/4 full. It has only happened two times in my life, and both times on my friends uphill driveway. I am sure it is siphoning the fuel back out of the filter, and if that is happening, then air must be coming in somewhere. I just can't figure out where.

__________________
1991 300D 172,000 (totaled)
1998 E300 Turbodiesel 82,500

Did you ever figure out the cause. I have the same problem. Will not start after sitting if pointed uphill. Roll it to a flat or downhill spot and it starts.
Thanks
Wendell