[stephen low]

Clearly not what I thought it was, by your description on cooling issues.

Does this fitting tend to cause recirculation until temp reached to minimise the time for the engine to heat up or has it a function to aid cooling at operating temperatures?

What temps were you running at Tony?

I ask as mine seems to want to stay cold, not much better than about 40 C, unless delayed in stop start traffic and then it moves to 85 - 90C when the thermo cuts in or more persistent forward movement achieves the needed cooling.

Your thread has made me wonder if I am missing a control mechanism as I replaced my thermostat but I don't believe my housing had been previously dismantled.

Does your thermostat have that nasty trick too of being ovaloid? Such that when you bolt it in incorrectly the first time you get all these coolant leaks until you re dismantle, swear and then put it in correctly again!!

Cheers