Helloo Guys.
Iv got a 1995 Mercedes W202 C250D and im having some issues as jools182. The car would start perfectly with the turn of a key when facing slightly downhill no matter how long it was parked but would not start when parked level or facing uphill when switched off for 4-8 hours. I've replaced the o ring between the shutoff valve and the pump(original), the two o rings of the shut of valve on the sides (not original as merc dealer was not able to find on diagram) , Fuel lines including their o rings(32,95,83,74,56)(original) , fuel filter including the two o rings on the banjo(original) , Pre-Filter and o ring (original) and still would not crank up. There seems to be no fuel leaks whatsoever but somehow i always find the line 56 empty. Ive also noticed that after turned off air begins to gulp air in the line from fuel heater to pre-filter after about 5 minutes. Some told me that i might possibly have a clogged tank strainer which causes the fuel to drain back into the tank but im not sure of this as i haven't went under the car. Once it decides to starts its excellent, doesn't miss and after a good run no air can be seen in the fuel lines while running. I would expect such things as he's 21 years old and moreover he only has 30,000 km. Glad if anyone can help as hes my daily and I don't like cranking too much as the starter is taking a good beating.