Thermostat housing bypass.

[Fuel.inj]

I noticed that my S2 running cold after a lay up so this morning I decided to replace the suspected thermostat and replenish the antifreeze.
When I removed the outer thermostat cover I was surprised to find that there was no thermostat installed?? and the bypass solid pipe was blocked not only with crud in the pipe but there is this sort of valve like a miniature horseshoe as shown in the photograph which seems stuck also. I am afraid to force it.
Does it come out? What does it do? Can it be replaced as I cannot find a part number for it.
Any advice will help as this job is not going well at all.

[mgcjag]

That is not the bypass its the air bleed vent..havent seen that little "jiggle pin" in there before but its quite typical for them to be fitted to a thermostat. It lets air bleed back. The thermostat isn't stuck in the houseing that you've removed is it?.. Steve

[Fuel.inj]

Hi Steve, there was no thermostat at at all. I just came across this item and part number in SC catalogue. Any suggestions? Do I just fit a new thermostat or do I bite the bullet and get one f these new valves?
https://www.scparts.co.uk/en/breather-valve/207514/

[abowie]

You should certainly have a thermostat.

C28067 looks to be the correct part.

I would leave the air bleeder as it is; it doesn't really do much.

I would humbly suggest you consider buying from SNG Barratts, rather than SC Parts.

[Fuel.inj]

Thanks for the advice Andrew. I’ve already purchased the thermostat and gaskets from SNG and after a little bit of gentle persuasion have just got that bleeder moving a little so I’ll just get it all back together and see how it goes. ATB. Paul.

[mgcjag]

Hi Paul.....you need to look inside your thermostat houseing where the foot of the thermostat meets to block off the bypass from the waterpump...if a prebious owner has removed the thermostat they may well have blocked the bypass....Steve

[Fuel.inj]

Just checked that now Steve and it’s all clear. I will put it all back together now. Will let you know the outcome.

[Fuel.inj]

Installed the thermostat, filled with antifreeze, run up to temperature, showing normal on gauge, fans kicked in as required. All seems normal thankfully. Thanks for your responses.