Technical Thermostat queries

[grubscrew]

Hi
I’ve the bellows type of thermostat, and as I was having issues re it not closing, I thought I’d have a look as to why.
Removal, all looked in fine fettle. The spring flap opens and closes as it should, without the spring , very freely.
Re affix the spring it wants to keep it open on the end of the flap shaft, is slightly stronger than the bellows trying to keep it shut.
There are two positions of the spring retaining cam, offering varying degrees of pressure open. ( I’m assuming there’s only one way it should be however, looking at press marks where its nut and spring washer fit).
So measuring the distance between the two positions shown it’s close to 138mms..
Also looking at the thermostat, I can open it slightly by hand. It does however seem to work when engine has been running , but when cold stays open around 25mm or so.
Also there are not as many ribs on this unit as a “proper” unit online. Have I a rogue unit….
or is it time to renew it any way.( me thinks yes).

 

[rusty500]

I don't have an answer to how to get the flap to close completely, but I don't think it necessarily needs to close tight. You can test if it opens properly by putting it in a pot of water with a thermometer and bringing it to boil. If I recall correctly, it should fully expend between 85 and 95C.

 

[grubscrew]

Hi , thanks for there is a temperature setting stamped on it,70*.
I think replacing it is prudent, as this was in an engine I had for some years and assumed everything was ok.
At least if a new one goes in , it’ll be as one expects.

 

[lazylobster]

Hi , thanks for there is a temperature setting stamped on it,70*.
I think replacing it is prudent, as this was in an engine I had for some years and assumed everything was ok.
At least if a new one goes in , it’ll be as one expects.

Install a new one, it's cheap insurance, if the flap does not open your engine will overheat and . . . BOOM!