Larry D,
It has been a long time (more than ten years) since my old 1975 240D returned to nature through corrosion of the body. The engine, however, was pretty strong the day my first new car got towed away with about 240,000 miles on it. Anyway, I do not remember every detail all that well, but I still have my manual. So, I just consulted the manual and it says to put the same oil in there as you would in the engine. It also shows a fill level plug and a really nasty sounding way to correct the level (the plug is on the driver's side, just aft of the hand pump - aft being toward the firewall). It also suggests the red cap has a filter in it. Well, I did not notice a filter in there, but I do remember a dip stick attached to the bottom, and I recall the oil in there was pristine after the car had about 30,000 miles. I never changed the oil, I just filled it up, too high as I noted in an earlier thread, as the oil was so clean I could not see it on the dipstick. Anyway, there is an overflow/vent on the IP, between the block and the IP, and the extra left via that port. I put Mobil 1 (which was a very light weight back then) in the engine as I was in Alaska and that made a big difference starting. So I put Mobil 1 into the injection pump too. The car never needed more of the stuff, the whole time I owned it, and the IP was in fine condition as far as I could tell when the body fell off (the engine ran fine) in 1992 or so. Hope this helps, 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)