Thermostats

[Alex Blair (RIP)]

Originally Posted by rob love

I would recommend the 160° thermostats. The temp rating is actually the temp at which they will close, and not when they open. Because the carrier is a relatively low pressure system compared to today's vehicles, you don't want to be hitting the over 200° temp range that a 180° thermostat will reach. I have seen some 180 thermostats not actually open until 240 degrees. Mind you, these are the low quality ones that you got from Cdn tire. Buy some good quality ones form Ford (use a pair of part number RT350) and trim them down with a set of tin snips so they fit.

When fitting your thermostat pay particular attention to how it fits in the recessed area in the head..make sure that the pocket is well scraped out of any rust or goop..
When you fit the thermostat housing over the thermostat and start your bolts in make one last check with a mirror and a light to ensure that the stat is still sitting down in the recessed pocket and that the housing is going to come down flush with the head..
I have seen the thermostat dislodge from the pocket and slide between the housing and the head and when the bolts are tightened down the thermostat housing cracks..usually taking off one bolt hole lug,.,..
So make sure it is in the pocket before tightening the bolt down.

[Ralph Volkert]

That explains the broken lug on my block! Was wondering why someone would tighten down a themostat housing so tight as to snap a bolt. And no it wasnt seized but it was a Pain in the A$$ to get out!

[ajmac]

Alex, that would only apply to Post 1948 Flatheads with the modern style thermostat housing at the front of the heads though, not the earlier type where the unit sits on top of the hot water outlet in the top middle of each head.

Earlier ones are only held in place by the rubber hose pressing into there circumference. The original wartime type with bellows would have had the bellows section sitting down in the water outlet pipe with the valve up at the top sitting on the end of the water outlet. Modern wax type are shorter so have very little hanging down in the pipe. When mine is rebuilt I am fitting post 1948 water pump impellors whch have a much increased flow rate and dosing the water with water weter, I haven't thought much about pressure caps, the post 48 had 4 Psi, but I am not sure about the truck style system fitted to the Loyd.