ffrenchepete Posted March 5, 2013 Report Share Posted March 5, 2013 During winter rides the Missus freezes. The engine temperature is around 65°c and the heater isn't happy, neither is the Missus. The car is fitted with an electric fan, which practically never cuts in, the engine isn't down on power, doesn't burn oil so the problem seems to come fron the thermostat. I notice that with modern replacement thermostats the suggestion is that the radiator by-pass hose should be blocked off. Surely, to get my engine up to 75-80° the by-pass should be operational and the radiator blocked off ? I see that parts suppliers are now listing the original bellows type thermostat (at a price of more than a full tank of fuel !) Would this be of any help ? Or should I put a cardboard barrier in front of half of the radiator ? Quote Link to post Share on other sites
Paul Harvey Posted March 5, 2013 Report Share Posted March 5, 2013 It will be easier to replace the missus, failing which search this Forum under "heater" and decide whether to replace the original heater with one that works. Quote Link to post Share on other sites
RogerH Posted March 5, 2013 Report Share Posted March 5, 2013 What is the temp of your existing thermostat - you may be running on a 'summer' stat. Check the thermostat and make sure the correct temp is fitted. The rad could be partially blocked of in the winter. Check the water flow through the heater matrix/heater valve etc. Put some rad flush in the heater to clean it out. The heater works well if hot water goes through it. Roger Quote Link to post Share on other sites
BrianC Posted March 5, 2013 Report Share Posted March 5, 2013 My understanding is that whilst cold, the thermostat blocks off the radiator, so whatever restrictor you fit in the bypass must have a hole (approx 1/4" or slightly more), otherwise the coolant actually in the block and head will not circulate, leading to local hotspots. (Probably totally wrong, but I'm sure others will enjoy putting me right ). Quote Link to post Share on other sites
ffrenchepete Posted March 6, 2013 Author Report Share Posted March 6, 2013 Thanks for the replies. The Missus doesn't feel in need of being changed. The thermostat is a 74° model. As RogerH says the heater works well if hot water goes through it. My problem is that the engine runs cold - 65°c; and the heater does what it can with the fluid available. I'll try the cardboard for a start - in 1966 after market muffs were the thing. Quote Link to post Share on other sites
RogerH Posted March 6, 2013 Report Share Posted March 6, 2013 Hi Pete, Are you in the UK if so, for the winter try using a 82' winter thermostat. That will delay the rad coming in. A sheet of card/tin foil will help significantly. Better still how about knocking up some thermostatically operated vertical slats (nickle plated) in front of the rad as per an early RR - I've an idea!!! Roger Quote Link to post Share on other sites
Badfrog Posted March 6, 2013 Report Share Posted March 6, 2013 Hi Pete, Find the right stat: AC bellows model, 82°C cut-in, with a moving flange blocking the engine by-pass when cold. Badfrog Quote Link to post Share on other sites
lynchpin Posted March 7, 2013 Report Share Posted March 7, 2013 This has been discussed lots of times in the past, I had the same temp problem and found the old type sleeved stat had failed wide open so the water flow to the rad stayed fully open and the engine never warmed up in winter. I tried a sleeved stat bought on e bay which still wasn"t very successful, I eventually fitted an 82* wax stat and inserted a 22mm copper cap available from plumbing shops into the bypass hose with a 1/4" approx hole in it, it stays in all year round and even without an electric fan the car has never boiled yet, (it probably will now), and the heater works fine.. Phil.. Quote Link to post Share on other sites
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