82-300td,

I think there is more likely something wrong with your glow plugs that is causing the low cold idle rpm and cold hard starting. The oil pump is basically a positive displacement pump, which means every time the shaft rotates it basically pushes out the same amount of oil. At lower rpm you will get lower volumes.

What does it normally idle at? Have someone give it throttle until it runs at that speed and check to see what the oil flow looks like. I have never personally made such an observation, and have nothing to offer in the way of guidance as to what a visual check of oil flow should look like. I have listened to these cars start and run with low oil pressure though, and they sound a lot more metallic and clanky.

The fact that you see oil running indicates you have oil flow, and therefore you will probably not do the machine harm running it until it is warmed up. You will kill the battery if you keep starting it for short operating periods and don't let the battery charge up, especially if you are cranking a lot due to bad glow plugs.

Good luck and I 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)