Installing thermostat

rscardina

rscardina

Senior Member
For those that have installed thermostats. Did you test the thermostat prior to installing it? If so, how did you test it?
 
In addition to what Mitch advised, I place the thermostat in a pan along with a meat thermometer. Turn on the heat and watch the thermometer rise to ensure it's fully open by the temperature of the thermostat.
 
"how" depends on how much you want to know. For most people, as Mitch stated, the pot of boiling water is a sufficient test to see if it opens.

To get a clearer picture, find the real set point, and determine whether you have a low-end fixed point 'stat or a better range-throttling stat you need an accurate thermometer and the 'stat both suspended in boiling water. Shut the heat off and watch for the point where the stat just begins to close. Now watch for the point at which it finally reaches fully closed. If the range is 5 degrees centigrade or less you have a simple low-end 'stat. If the range is about 10C you have a throttling 'stat.

The 'stats are operated by a small brass cylinder with a SS pin/piston. The cylinder is filled with either a single molecular species of wax or a compounded wax. When the wax changes state from solid to liquid it expands, pushing the pin/piston up.
Stat.jpg

The low priced simple replacement stats (most common) contain a single wax that behaves physically in a very eutectic manner. As a result, the stat is either open or closed at a fixed point.

Just like metals can be mixed to make alloys, most of which are non-eutectic, waxes can be mixed to give a varied solidification range and final solidus point. If you use a more complex wax formula like this the 'stat behaves in a throttling manner which make for a very smooth and consistent temperature regulation in the engine, no direct on-off blasts of cooled radiator water. Many OEM and higher-tier replacement stats behave in this manner.

My own experiences and testing show that the 160 and 180 'stats attached to the short tube sections, as sold by the A parts vendors, use the simple, cheaper on/off stats.
 
MikeK said:

My own experiences and testing show that the 160 and 180 'stats attached to the short tube sections, as sold by the A parts vendors, use the simple, cheaper on/off stats.
Click to expand...

The 'stat that I got from Snyder's for my Town Sedan seems to miss the 'set point' as the temperature rises to ~170°F before it catches and falls to ~150°F. Then cycles back up. Each 'cycle the temperature range decreases until it stay relatively steady the longer I drive at 155-160°F .

Do you or anyone else know of a "high end" 'stat that will fit in the top hose with better control? I figure I could then tack that 'stat to a short piece of tubing like the "store bought" ones.
 
Y-Blockhead said:
The 'stat that I got from Snyder's for my Town Sedan seems to miss the 'set point' as the temperature rises to ~170°F before it catches and falls to ~150°F. Then cycles back up. Each 'cycle the temperature range decreases until it stay relatively steady the longer I drive at 155-160°F .

Do you or anyone else know of a "high end" 'stat that will fit in the top hose with better control? I figure I could then tack that 'stat to a short piece of tubing like the "store bought" ones.
Click to expand...

Actually what you describe, ~170F - ~150F max range is pretty close to the 10C (18F) range I mentioned for a throttling 'stat. For an engine with no internal recirculation during the time the stat is closed your 'hunting' driving experience is pretty normal.

If you want to try a do-it-yourself setup try the Stant 45356 160 degree SuperStat. It throttles better than their standard 160 'stat. About $9 at my local modern parts store. Expect to do some trimming/grinding on the flange O.D. if you tube mount it. The vendor tube mounts hold their stat a bit too high for my liking. If you tack weld the tube on the rad side instead of the engine side you can it get lower, closer to the outlet casting. That will reduce the initial overshoot.
 
I tested it this evening. As the water was cooling off to 176F 80C it began to close. It closed completely at 150F 65C.
 
Whether you're running a thermostat or NOT, at constant cruising speed, you see a drastic UP & DOWN temp sweep, every 2 or 3 minutes, YOU'RE LOW ON WATER!!!!!
Bill W.
 
Hey Mike,
If you think/like the 'stat' closer to head outlet, do you see any advantage/value to using the part made to hold the stat and that attaches to the head outlet ?
I realize that this gizmo is not stock. It also has a bung to attach a temperature guage and that seems good idea.
 
hardtimes said:
Hey Mike,
If you think/like the 'stat' closer to head outlet, do you see any advantage/value to using the part made to hold the stat and that attaches to the head outlet ?
I realize that this gizmo is not stock. It also has a bung to attach a temperature guage and that seems good idea.
Click to expand...
Works great!
 

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rscardina said:
I tested it this evening. As the water was cooling off to 176F 80C it began to close. It closed completely at 150F 65C.
Click to expand...

If it is easy to test which it is, then It is a good idea to test before installation. Better to know you have a faulty part before installation so you don't have to do the job twice. Any part with moving parts is subject to a productin error. So test it for the peace of mind if nothing else ! Wayne
 
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If some hesitate to put in a thermostat because of FEAR of failure, modern thermostats RARELY fail. Most common failure I've seen, is one of the side straps break, cause the valve to "****" over & suddenly the car runs COLDER!! If this happens, replace the thermostat QUICKLY, BEFORE THE OTHER SIDE STRAP BREAKS & it WILL overheat QUICKLY!!
Bill W.
 
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