Thermostat & By Pass
Early SY models (prior to VIN 2832) were fitted with thermostats that started to open between 79.5C and 83.5C. From 1966 (VIN 2832) an 88C thermostat was fitted which started to open between 85C and 89C.
We have become increasingly aware of engine problems being caused by engines running too hot. We feel that this is partly caused by the ethanol content of modern fuels but we are definitely seeing an increase in problems related to the bottom half of the engine overheating. As a result, alongside the 88C thermostat UE36600P, we have manufactured UE36600-78P which is designed to open between 75-79C and to be fully open at 88C. As per the original thermostat these have been manufactured to include the fail-safe lead pellets, which are designed to melt if the engine gets too hot and allow coolant past the thermostat.