[TR] Triumphs Digest, Vol 1, Issue 232

[Art McEwen]

Right but without flow between the water pump and the heater core the 
water in the heater core will remain at room temperature except for 
radiant heat, which would be slow.  And as it warms reasonably in time 
with my gauge moving it must be flowing and therefore the thermostat is 
at least partially open.  If it was stuck fully open it's supposed to 
block the heater hose plumbing so the heater core wouldn't be as 
effective, but a stuck open thermostat wouldn't contribute to overheating.

As I say I'll replace the thermostat anyway but I think it's likely fine.

I think it's likely the new, less efficient, grill combined with a 
fairly dense rad core (re-cored locally) and a few miss-bent fan 
blades.  That and local weather/traffic well in excess of the british 
designers original criteria ;)
>   
>> I haven't yet, it's at least open as I feel heat in the 
>> heater core fairly quickly, 
>>     
>
> That's kind of a non sequitur ... rapid heat means the thermostat is closed,
> not open.
>
> And doesn't really tell you anything about whether it opens when it should,
> or if it opens all the way.