Hello! 

I have a Pinto SOHC. . The Thermo bypass has been stoppered since before I gotthe car as a PC project. What I find is that the the (mechanical) stat doesn't want to open when the engine is hot. Is it because there is no flow of hot water over it? Should this stoppered bypass actually allow water to flow over the stat allowing it to operate?

I've replaced teh stat anyway (had a spare) but in any case when tested the stat worked. Originally I believe it had a header tank, but now has omne of those rads with an integral header and pressure release cap.

 

That is not a bypass as such it was an air bleed to the header tank in a sierra.

It did allow some flow via the header tank to allow the thermostat to work from cold.

Most people drill a 3mm hole in the flange of the thermostat to achieve the same effect.

2 minutes ago, IanS said:

That is not a bypass as such it was an air bleed to the header tank in a sierra.

It did allow some flow via the header tank to allow the thermostat to work from cold.

Most people drill a 3mm hole in the flange of the thermostat to achieve the same effect.

Aaah, thanks Ian, and thanks for the tip! I really didn't think of that.

So the bleed can be stoppered with teh assumption that any air accumulating at that point will be eventually blown into the rad?

The air will only go into the top tank of the radiator reliably if the top tank is a bit higher than the thermostat.

5 minutes ago, IanS said:

The air will only go into the top tank of the radiator reliably if the top tank is a bit higher than the thermostat.

Yes, definitely is.That's brilliant, thanks Ian!