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1.6D thermostat height

Posted: 14 Nov 2011, 20:00
by Oldiebut goodie
2nd ever question from me!! :mrgreen:
Is the lower flange of the thermostat supposed to meet the outlet at the bottom of the housing? The listed thermostat has a height of 31mm between flanges whereas the depth in the housing is 41mm with the result of not shutting off or restricting this outlet when cold. This makes the smaller flange pointless as a shut off or even as a restricter.
Has anyone ever queried this fact before and found a solution?

Re: 1.6D thermostat height

Posted: 15 Nov 2011, 15:27
by Oldiebut goodie
Come on someone must know! :)

Re: 1.6D thermostat height

Posted: 15 Nov 2011, 21:27
by colinthefox
The thermostat is not supposed to restrict the bypass circuit when cold, so that coolant can circulate round the engine without going to the radiator. As the engine warms up the flange moves towards the bypass port closing it down, and the other flange opens the radiator circuit. When fully open the thermostat has closed the bypass completely by moving 10mm towards the flange you mentioned, and the radiator circuit is now wide open by 10mm, so now all the water goes round the rad circuit and gets cooled. Cunning eh?

30mm plus 10mm =40mm

Re: 1.6D thermostat height

Posted: 15 Nov 2011, 22:01
by Oldiebut goodie
Thanks for the input.
Maybe the reason that I cannot see any closure is because I am sitting here with 2 duff thermostats - the maximum movement that I am seeing on heating them up in water is 5mm.
I'll see what another new one does tomorrow!

Err.. and yes I meant hot really - must wake up before I post and proof read also. :oops: