I took pictures immediately after pulling each of them out of boiling water. they were in boiling water for at least 5 min.
All of them brand new from NAPA.
One of them opened twice less.

Make sure to use the working one then.

How is the work on your cooling system going by the way? You were the one that had the system that was beyond rusty and nasty. Have you replaced all components yet?

Yeah, I'd say that's pretty crappy.

I believe OEM t-stats are the way to go.

I think I'd use the middle one.

I drove it about 20 miles today.
It was kind of OK, but I felt that electrical fan was working too early. Here is picture answer.
I boiled chosen new NAPA thermostat and Advance auto one, which I installed 3 days ago.
I am going to check fan clutch too.

Why would u expose a stat to boiling water? Why would u test without a thermometer? Coolant in the motor shouldn't be boiling. When installed in the motor, a stat isn't exposed to the sudden cool of ambient temp either. Pics show a 180 stat under similar conditions as when in the motor.......not exposed to boiling water, not exposed to ambient air temp.

Boiling water has 212F temperature. At this temp any thermostat has to be completely open.
I could see opening gap in water, I just pulled them out to take pictures.
You don't really need thermometer. Even if you do, you need to know:
temp of beginning of opening
temp of fully opened
You also need to measure temp of thermostat, which is impossible. If water is let us say 195F, we don't really know how long it will take for thermostat to warm up to that temp. 3 min.? 5?
Boiling water is reliable and simple way to check, unless you live in mountains.

What????? U're kidding, right? It's very clear in the pics I post that a properly functioning 180 stat is closed at 180 and is wide open (or very close to it) at 195. U do understand that a properly funtioning stat will "hover" in an infinite number of more or less open positions between full closed and full open, no? I didn't have the time to show pics of the infinite number of open positions. U do know the meaning of infinite?...............................and who buys 3 t-stats?

We check different things and you do it right.
You check temp of opening, I check how far they open. I have bought a few bad ones, so I just don't trust Advance and NAPA.
If you like wasting your time by buying bad one and then buying again, it is OK.
Or maybe you buy from better place, where?

Yes water boils at 212F but when mixed with antifreeze it boils at a higher temperature.

I think you guys are trying to pick fly chit out of pepper.

Rockville, here are are couple of pics of the OEM 195* thermostat (which you should buy) which you can and to your collection of pics.

OEM part number 97-2K1 part number 52028186.

Note the bleed valve in the stat.





This stat is for a 2K T&C but the 8186 stat is the same design.

Or just buy an OEM mopar stat for about the same money and sleep easy. My experience with them is that they're the best in the business.

I have NOT had a failure of an OEM Mopar stat in 38 years. Not a bad record. No way I'm messing with aftermarket.......

Only thing I'm picking fly chit at is the worthless apples/oranges stat "testing" method (boiling water).

I don't consider testing a t-stat prior to installation a waste of time. Neither NAPA or Advance make a t-stat. What does NAPA or Advance make......anything? Stant is the only brand of t-stat I've ever bought/used and always had good results but again, I test before installing (just not in boiling water, duh). I've never returned a Stant after testing or had one fail while in use. With all due respect, I'd almost be willing to bet that Stant quite possibly made that Mopar t-stat. Auto manufacturers, for the most part, make doors, fenders, hoods, frames, motors, etc. Most of the small parts (maybe t-stats for example) are subbed out to be made by other companies or subsidiaries.....thus the term Original Equipment Manufacturer or OEM part(s).

http://www.stant.com//Automotive-OEM...em-Components/

Note the Chrysler Pentastar on the thermostat in the above pic. If the small part carries the Chrysler part number and/or has the Chrysler P'Star, it can be concluded that that the part(s) are made to Chrysler drawing standards, and maybe even be subjected to Chrysler QA audits.

I agree with not dicking around testing parts from the after market carpet baggers...Simple really: Buy MOPAR parts.

I'd almost bet Stant is licensed by Chrysler (and others) so there's a P'star stamp (maybe a GM and blue oval stamp also) at the Stant manufacturing plant where Stant makes the stat to Mopar's specs, part #'s and packaged in a box with the Mopar label.