Old thermostats

[Toby]

As I’m getting ready to finally get the engine back in my car I’ve been preparing all the bits it needs. Now I’ve come to the thermostat for it. I happen to have two new old stock ones which I wanted to use one of.
Now prior to installing I thought it would make sense to test them. And it’s a good thing did a neither seems to be working anymore.
I stuck them individually in a cupboard boiling water and they don’t move. If pressure is put in them by hand they do open.
Couldn’t be that the wax has gone off over the years?

[Spider]

Sometimes they come good after a few heat cycles, so I'd suggest trying again a few times before discarding them.

Interestingly, the one on the left, long long NLA, looks like it is the original type for which heads with the By-pass were designed to take. As it opens, it covers over the By-pass port in the head.

[Toby]

Trying to hear them up a number of times to try and coax them back into life is a good idea.
Interesting fact about that left one, thanks for that

[gs.davies]

Just wondering why you’d risk using something like that which can give a headache quicker than you can catch it in the act? It’s not like a better modern version isn’t available or detracts from appearance. Or am I missing something?

[mk1]

The problem with a lot of NOS items like this is that they are often not NOS. They are faulty items that have been removed from a car & put back in the box that the replacement item was supplied in.

To my eye both the above stats, but particularly the one on the right look used.

M

[BAD942B]

one other thing, the early bellows type is filled with alcohol & stays shut when they fail, the later waxstat type are supposed to stay open when they fail or that's how they were explained when I was at college in 1974 to 79