I rigged the aux. fan and it didn't help me one bit. This led me to believe I had bigger trouble. If you check the last post on the previous thread you will see that I deduced that it was the thermostat. ( I arrived at this conclusion because I can't afford a water pump right now!) I tired everything to get the car to run cooler, heater on, aux. fan running continuously etc. When I checked the radiator it was cool to the touch. Then I checked the top WHEW that was hot! The bottom was cool to the touch....THERMOSTAT! I found one in stock at a FLAPS finished my route and promptly broke off one of the bolts that hold the cover on the t-stat. I now have the thing put back together and it hasn't gotten over 180°F . ( with the heater off, and the aux. fan off )

What started pointing me in the T-stat direction was this..
1) I had heat coming from the heater
2)The engine was running progressively hotter up to around 210° at one point.
3)I couldn't afford a water pump
4) I couldn't see any circulation in the radiator with the cap off.
5) An additional fan did NOTHING to aid in cooling.
6)Top of radiator very hot and bottom of radiator very cool. (the tanks)
7) Radiator core itself was very cool, like the bottom tank.
8)Top hose was hard (psi) bottom hose was not as hard...only steam getting into the top hose?

Anyways, a '76 300D takes the same T-stat as a '84-'86 Jeep Grand Cherokee and some Lincoln Continentals-like '83-'89? Several Audi's etc. I also learned that the oil filter in the '76 300D (W115) is the same filter that is in old Ford 9N tractors! That means I could even get oil filters at County Post/Quality Farm and Fleet. No more driving all over looking for oil filters