Antique thermostat
 

I am working on the cooling system for my 51 3100. The 235 in it is a replacement. No idea what year. I removed the thermostat to inspect it and was surprised with an unfamiliar object. It is obviously a thermostat but instead of the familiar cylinder with a spring coiled around it it consists of a bellows as big around as the opening it rides in.
What I'd like to know is how long ago this style was replaced with the modern version.---Jack

Re: Antique thermostat
 

That may well be an original. They did use them in trucks in the 50 early 60's but not much after that. I'd hang onto it for a paper weight or something. Can you imagine the cost of that today. I'd bet $60 or so

Re: Antique thermostat
 

My thoughts also.I was thinking of shinin it up a bit and hangin it from the christmas tree. A true redneck decoration.---Jack

Re: Antique thermostat
 

There ya go.

Re: Antique thermostat
 

Don't know the answer to your question, but I had the same kind in my truck.

Re: Antique thermostat
 

That's the same type as in my '36 Plymouth. When I was getting the car ready to drive after sitting since '59, I bought a new thermostat. Wouldn't you know... it was sticking right out of the box. I went back to the old one! I believe the last company to use that 'stat was Robertshaw. They might have produced a version of that design until the company was bought out in the '80s or '90s. Production cost was higher so they became a fairly expensive thermostat. Go to google and do a search in "images" for "robertshaw automotive thermostat" and I believe you'll see newer versions sold by Stewart, who bought Robertshaw.

Re: Antique thermostat
 

I was thinking he meant one like this. The robert shaw type I've seen in the 80's

Re: Antique thermostat
 

xmas ornament ? v v cool

Re: Antique thermostat
 

To DWCSR: That's it.Mine looks just like that. As close as the 80s. That sounds about right. That is when this truck was last worked on.---Jack

Re: Antique thermostat
 

Thermostats have progressed and changed shape over the years. Most have changed to a wax pellet design with a spring to force the valve closed but the Robertshaw continued to use a bimetal bellows long after the others. At some point the bellows became sleeved and not visible. I just meant that a person might see what the last version of the bellows type 'stats looked like compared to the early ones by looking on the 'net. Here's my old Plymouth one.