ck42,

Congratulations! Glad to hear things are back together and working well.

The flow rate is pretty much normal. You have a relatively light heat load at idle and the thermostat is mixing the water coming from the hot engine with the water coming from the cooler radiator to maintain a fixed temperature. Since the flow through the radiator is proportional to the heat load, you are not seeing much flow under the conditions you observed. If you were at full load with the engine at high rpm, the flow rate would be substantially higher. The pump output increases dramatically with rpm and the thermostat will recirculate less hot water and draw in more cooled water, both of which will make the flow through the hose you were observing much higher.

Hope this helps, but it sounds like your engine is doing fine. Is the temp stable at around 80 degrees C? If so, things are fine. Good Luck, 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)