Hello all, need some help about air getting into diesel. I have a C250TD 1996. There is air getting in to the injector pump somewhere and I cannot find where. It's fine when it's running, but if sitting for a few days, it will fire once or twice then will not run until bled. I have replaced all o-rings on tubes that supply fuel to/from filter/injector pump. I've checked the feed from the tank and I've replaced the injector return tubes but it still gets air slowly from somewhere. Does anyone know of any likely/common problem? Appreciate some help, it's driving me nuts! Thanks Scott

 

Had a problem just like this about ten years ago. Cost me close to a grand in the shop over a week. The problem would still be there when I went to pick it up. The last time the mechanic a I were looking at the engine as it was shaking and sputtering and I asked if there was supposed to be foaming air bubbles going through the (clear) air filter. The hose going into it was cracked. $10 fix..... idiots!