coachgeo,

I think if you submerge one of these fans you may ruin it as I do not think they have sealed bearings and they use brushes. Water is not recommended for soaking either of them, especially when in use. You may try one though to check out the set up and then make it easy to remove when you go into deep enough water, if that is even practical (I imagine sometimes you may not have a lot of notice about the depth of water). In the end when you find the time and money you could substitute something a little more suited to this kind of abuse.

When you harvest one from a boneyard, follow the power line and take as much of what is connected to it as possible. This should lead you to the sensor as well. I am sure your car has something plugged into the sensor spot, which is either on the head or on the thermostat housing. You may want to take the thermostat housing from the donor car if that is where the sensor is plugged in, as the one on your car may not have all the necessary ports for the extra sensor.

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)