[steve25]

A 180 stat will start to open at about 183 and be fully open close a tad above 200.

I find it best to use a thermal gun and once the water starts to make small bubbles turn off the heat and remove the pot from the stove, then with the gun watch until the temp gets down to 205 and only then drop the stat in.

It’s best also to do this test in a large volume of water so the temp drops slowly before you drop the stat in.

[HWYSTR455]

I prefer the conventional spring-type stats, less of a chance to hang.

Not sure why they call that type 'high flow', seems to me it would flow less than the spring type. But may just be the way my brain works.

Conventional spring type you certainly can see them open and close, with ease.

.

[68 Firebird]

Had good luck with Superstats years ago.
Been doing NOS ones off eBay and very impressed.
Years ago picked up a NOS AC Delco 170 for a corvette.
When tested it cracked open at 167 and fully open by 185.
When in use my gauge stays at 170ish around town and175ish
On highway in the heat. Drops right back to 170 when back
On side roads. Bought another as a spare for garage art.
This is with a standard duty fan clutch!!!

Gerry

[Skip Fix]

Originally Posted by HWYSTR455

I prefer the conventional spring-type stats, less of a chance to hang.

Not sure why they call that type 'high flow', seems to me it would flow less than the spring type. But may just be the way my brain works.

Conventional spring type you certainly can see them open and close, with ease.

.

Me also on the flow.
My engineer dad would always test them in a pot of hot water when he thought that was the issue

[Terry M. Hunt]

Dug out the original 195 unit that was in the engine previously to test it and get a better idea of how to recognize when it was opening. It still works fine and the opening and closing events were obvious. Bought the 180 Napa stainless steel version and tested it with my infrared thermometer instead of the meat thermometer used previously and it worked just fine. Tried the infrared on the Robertshaw a couple more times, but I swear I can’t detect that any movement occurs even up to 220 . Makes me very reluctant to use it, so I guess I now have another piece of garage wall art to hang up.