Ahhh okay. I was thinking that they so rarely ever fail closed. Mine literally fell apart the moment I removed it; corroded but clean. Cooling system flush? Bypass your heater core during the flush. Perform an independent flush of the heater core. Sometimes flushes cause leaks as the deposits are the only thing preventing them.
The one that fell apart the second I removed it, still worked perfectly before removing it. Note, "rare" does not equate to "never". Rare can mean, "unlikely".
The Motorcraft replacement thermostat is 190 degrees. My 1995 Factory Service Manual says that the thermostat should start to open at 192 degrees.
I have seen a stant thermostat that I took out of one of my Escorts that had a 195 stamped on it, instead of the 190 that I expected.
Start ,and other manufacturers, make ones of various temperature ratings that will fit. The real question is where to get just a thermostat gasket. A search usually only gets me just a thermostat housing gasket, but what if all I wanted to do is to replace the thermostat gasket? Also, according to the FSM, the thermostat start to open temperature can vary, but the fully open temperature was the same.
If you look at the pictures for the Motorcraft thermostat, it clearly shows 192 stamped on the bottom.
I have had bad luck with autozone tstat. I had to switch them every year for like 3 years. Just an FYI if it reappears Sent from my LG-H872 using Tapatalk
Rock Auto used to sell just the thermostat gasket. I've seen them on closeout for a few cents each a few times when I'd make other orders and add them to my present order so it wouldn't effect shipping costs.
I've used Stant several times over the years and they've always been good. I put a Duralast in my '88 Pony one time probably 20 years ago, it opened too early and the car never seemed to get up to temperature during cold weather.
"...it opened too early and the car never seemed to get up to temperature during cold weather." So it was a "Performance thermostat"!