Om642 Thermostat

[MrGreedy]

That one looks to be in the closed position, though, and from your symptoms it had failed in the (fail-safe) open position. The seal only seals it in the closed position.

Yeah, maybe I'd been fiddling around with it. It's certainly possible that detaching rubber seal had managed to get itself wedged around the seating/sealing surface.
It was inconsistent as well. Sometimes I assume it must have closed, and others I struggled to get the car up to temp when very cold.
It gradually was getting worse, so whatever the fault, I'm glad I changed it.

Based on your 92°C comment, if that's the case, then when I'm next ordering something from Autodoc, if I can find one for around a tenner, I'll buy one to see if the brass nipple/insert thing is removable. It might give me a spare stat. And if you can buy one with a spare thermostat housing gasket, all the better. They (just the gaskets) are (were last year) £22 from Merc and like rocking horse doo doo.

 

[OneForTheRoad]

Those are all unheated versions. Now if you could identify an unheated housing that is otherwise identical to the heated one, game on apart from maybe the resistor...

Or eviscerate the heated housing, and (unless the eviscerated housing then leaks, and I can see no reason why it would, or there's not quite room for the plain thermostat below what remains of the heater element), game on again apart from the resistor...

Worst case, you've bought a 'stat that you can't make fit, and you then have to buy an OE heated version. The only way to find out is to try it and see. I hadn't the time, or I would have done so...

The one pictured is maybe the heated one , it's on the same page with the single stats . Worth a punt like you say .

 

[votnus24]

New input: car was of course not getting up to temperature, it got to around 60 degrees and then, it went back to the begging - as a cold engine. When i parked, i heard the cooling fan was spinning. Why would it run if the engine is cold. Now, the thermostat is probably due to replacement very soon since in summer when going downhill the car would still drop some degrees, but now, what else should i check? Temperature sensor surely has some defect to it. What else?

 

[E55BOF]

Replace the thermostat, and take it from there.

 

[b21playa]

Any links to the insert thermostat?

 

[OneForTheRoad]

Any links to the insert thermostat?

Autodoc and look.

 

[OneForTheRoad]

Any links to the insert thermostat?

 

[votnus24]

i replaced the whole unit, housing included. It was from AIC and it works great!

 

[b21playa]

Just to update I swapped the whole housing with a Borg & beck one and back to normal. Looks like the one old the rubber seal failed which didn’t allow full closure

 

[OneForTheRoad]

Just to update I swapped the whole housing with a Borg & beck one and back to normal. Looks like the one old the rubber seal failed which didn’t allow full closure

Yep that's goosed .