PeachParts Mercedes-Benz Forum - View Single Post - Curious: What's that OTHER cap on the back of my 240D injection pump?

JimSmith · #9 02-09-2002, 10:21 PM

Larry D,

While my recollection of a dipstick seems to be questionable, the bent tube between the block and the injection pump should be there in any case because I clearly recall pouring a quart of Mobil 1 in the late 70's into the port covered by the red cap, only to discover it was running out the little tube. And on to my buddy's father's driveway. Made a mess that took me a long time to clean up.

Since I found no easy way to drain the excess out, and the car ran fine, I assumed the tube was intended to expell any excess fluid. In my old manual for the car the tube is called the "overflow pipe." In your situation, I would be inclined to pour oil in there and see if the excess ran out the overflow pipe. If it did, I would flush that way.

My old manual shows the intended level check plug as a small bolt about an inch or so aft of the hand pump, and about an inch or so up from the bottom of the pump. The instructions say to pull the plug and if the oil level is below the plug, add some in through the port with the red cap. If oil and Diesel leaks out, you are supposed to loosen the regulator cover and raise it slightly to let the stuff can run out. There is no identification of what the regulator cover might be, so I would get anxious at about this point and revert to pouring oil in until the overflow pipe started running. If Diesel fuel is mixed in and that is unexpected (my manual suggests this is normal) and you want to get it out, I would check to see if Diesel floats on your engine oil. If it floats, then you can pour some more oil in until the stuff coming out is clear oil.

Hope this helps. Jim