OM 646 Thermostat

[Trickythemerc]

The way this happened an air lock is very,very unlikely. I was in slow moving traffic with the heater working as well as it should be. Next thing I am feeling chilly, checked that I hadn't changed any settings and drove home and checked the obvious stuff then went to the pub

 

[E55BOF]

Curiouser and curiouser...

 

[Trickythemerc]

Any excuse to go for a pint "Said Alice"

 

[Trickythemerc]

Update and a change that I hope will confirm a stat issue. Today I had to go and meet Tommy Fleetwood. The journey to his house was 35 miles and the heater was warmish, returning down the motorway things changed and by the time I got close to Manchester it was stone cold. I spent fifteen minutes having coffee with my customer in Manchester, back in the car and within 2 miles I had max temperature and had to turn it down. Confused as fook.com

 

[E55BOF]

I've never known anything like that, but you're getting there, I think. If the mechanical side of the heater innards is serviceable, with the flaps and motors all doing their stuff properly, I can't see how it's anything other than a problem with either a haywire cabin temperature sensor or its controls, or (much less likely, I'd think) coolant flow through the heater unit, though, not the coolant thermostat.

 

[Trickythemerc]

I Have done a kettle test on the new thermostat, bang on @ 92c fully open when tested using my Fluke infra red. So fitting it will eliminate it from the process. I have considered the cabin temp sensors and or the control panel and will investigate further if the problem persists. I have another longish run on Monday so I will see what happens then.
Thanks for your input thus far.

Tricky