Does the wax in thermostats lose its temp range?

Got an old thermostat on the mighty '67 Evinrude V4 60 HP. Copper body containing wax that pushes up a rod to move the valve. Was seized. Freed it up. Put it in a saucepan on the stove and the wax still pushes the rod up. I don't have a thermometer to measure the water temp so I don't know if it's opening when it should. Goes down under the spring pressure when cold. Does the wax lose its temperature range over time or is it the case that if it pushes the rod up all is well?

Re: Does the wax in thermostats lose its temp range?

thermostat should open before the water in pan boils. 212F I would think you can judge when the water is about 180 F. Too hot to put finger in. I have never seen a thermostat change temp where it should open so I guess the wax is good to go.<br />Good luck

Re: Does the wax in thermostats lose its temp range?

The ususal problem when they fail is they get stuck either in the open or closed position. The physical properties of the wax do not change over time.

Re: Does the wax in thermostats lose its temp range?

Hey Tink....why ya' messin' with an old T-stat? Get a new one. You put to much work into the old shaker to trust a used t-stat.

Re: Does the wax in thermostats lose its temp range?

The wax probably doesn't lose its properties unless severely overheated. It is retained inside the themostat element (Vernatherm) by a membrane. If it gets to hot, the membrane will break and the wax may leak out and change the calibration of the thermostat.<br /><br />If yours is original, that is a lot of years to go on a thermostat.

Re: Does the wax in thermostats lose its temp range?

Thanks all.<br /><br />It was opening well before boiling point and the wax isn't leaking out, but maybe I'll take the safe course and ditch it in light of the warnings about its age. I don't know how old it is but if it's seized it's not in top condition.<br /><br />This thread is just the result of more tinkering and more Tinkerer stuff-ups. It was seized so my natural response is to clean it up and see if I can free it or break it in the process. <br /><br />It came with a salvaged thermostat housing that I was forced to buy after my stupid dog knocked mine off the hanger it was on after I'd spray painted it last week. The one time I didn't hang stuff off the roof. Shattered a barb, which I didn't discover for a while as it had masking tape around it. The clever repair I did with auto heater hose barbs by sleeving the housing tube and putting on another barb with high temp glue restricted the tube circle by about 40%. The sleeve was already drilled out to the max. I was worried that 40% restriction would reduce water flow too much and cause overheating. I was lucky enough to get a thermostat housing off a junk motor for $30 after being quoted $300 at the main parts place. The dog was lucky too because when I got the $300 quote I started thinking about turning the dog into a rug.

Re: Does the wax in thermostats lose its temp range?

I,m with OBJ,get a new one & dont waste time thinking about it,just not worth the thought.Go fishin

Re: Does the wax in thermostats lose its temp range?

When you get your new thermostat, run the test with the old one in the same pot It should satisfy your (and my)curiosity.

Re: Does the wax in thermostats lose its temp range?

Tested it tonight several times with a cooking thermometer. Thermometer is probably more accurate than your average temp gauge 'cos precise temps matter more in cooking than gauge ranges of cold / normal / hot / something broke while you weren't watching the gauge.<br /><br />Thermostat opens consistently at 155F and reaches half open if left at 155F.<br /><br />Consistently reaches full open at 160F.<br /><br />So it has a 5 degree range. <br /><br />Book I have says normal operating range for this motor is 130-150F. Over 170F is bad. This thermostat opens 5F past normal operating range and is fully open 10F past it and 10F under limit.<br /><br />More time wasted tinkering but tinkering is educational because now I know:<br /><br />1. The temp range for this motor.<br /><br />2. This thermostat is stuffed<br /><br />3. What the insides of it look like.<br /><br />4. You can get a cooking thermometer at a department store cooking section for about $6 or about the same thing at an auto store for $40.<br /><br />5. The proper cooking temperatures for fats, toffee and so on.<br /><br />6. The stuffed thermostat is worth nothing (unless I put it on eBay) but a new one costs $60.<br /><br />7. I could have saved the $6 on the cooking thermometer, not to mention the time chasing it up and getting it, if I'd listened to OBJ, seahorse, and Fucci, but then I wouldn't be able to cook toffee of different hardenesses as the cooking temp determines the hardness, which isn't something most people know.