I just bought a 1990 740GL sedan, auto, for $60! 220K. The only major thing wrong with it was loose of coolant from a failed heater control valve. Previous owner may have overheated the motor. Now that I fixed it, the motor runs fine with perfect temp level. Drives great.
There is a strange sound now, kinda like a minor heat shield rattle. I believe it is coming from the front engine area. I stopped the fan form spinning on the fan clutch with a wooden stick when the motor was idling and the sound seemed to get less. Could be the fan clutch or water pump? When I open the coolant cap the pressure is relieved and the sound seems to lower as well.
Problem: There is a small amount of oily stuff in the reservior so I flushed out the sytem again and then this oily stuff, however very little is there again, not really a whole lot. Also there seems to be alot of pressure in the upper top raditor return hose from the thermostat. Shouldn't this hose be soft to squeeze? Could it be the radiator is clogged and all the coolant is being backed up in the top radiator hose and this causing strain on the water pump?

This car was sitting for months with no coolant in it so some rust was present when I filled her up and then I did a second flush. Should I reverse flush the radiator?

I would like to sell this car for a little profit after fixing it up a bit.

1987 740 turbo wagon 220k
1990 740gl sedan 220k