I have several theories:
1) There is a flap open somewhere letting in a large amount of outside air.2) The coolant valve is broken, corroded, and though it moves easily with fingers or vaccum via diaphragm, it's not letting hot coolant into the core.
3) Since I can put my hand on the lower radiator hose at full running temperature and it's not even warm, my thought is a bad thermostat. What is the regular operating temp of these 300 diesels? Seems like it ought to be around 90-100C. I've put cardboard in front of the radiator but haven't had time to see if that helps on a long enough trip, it's only 7 miles to work.4) The "amplifier", whatever that is, isn't working.
5) All the insulation is torn off the underside of the hood. I wondered about using contact cement to attach a layer of ReflectixOur 2001 VW TDI provides heat like hell...what am I missing?
Sincerely,
Kevin