Worked on the racecar cooling system again. After about 10 years of only running water as the coolant, there is tons of rust and scale built up in it. We rinsed it again and then let some CLR sit in it for about 3 hours. It removed a ton more junk, but there still doesn’t seem to be much flow through the cooling system. We did finally get a temp reading on the coolant temp gauge inside. At this point we are going to ask on the E30 forums if there should be coolant coming out of the bleeder immeadiately or not, which might change our approach. Barring any good suggestions from the query, we will be replacing the thermostat, thermostat housing, and water pump, as well as flushing all other lines directly.