External Thermostat Testing?

[Craig Roche]

I've searched the board and I'm still not sure how to test my external thermostat. I have it removed from the car. I read that you can put it in boiling water? Is it ok to get water inside it? What do I look for and where?? This rookie needs help, please!

My plan was to take it apart and replace the internal pcs. but I can't get the caps off (silly design). So, I thought I would try and determine if the thing is working properly. Seemed to work before I took the car apart, at least it didn't seem to overheat.

[WERK I]

Craig,
Testing it is pretty easy. The only cap you need to get off is the large one. I use a visegrip, locking the jaw around the circumference of the cap. Don't lock the jaws too tight, rap the end of the visegrips lightly with a rubber mallet. One soft rap should loosen the cover. Once the cover is off, you can slide the valve out of the unit. Before dropping the valve into boiling water, note the valve opening. Drop the valve into the water, wait a minute, use tongs to grab the valve out of the water. You should see the piston in a new position.