In the home stretch of a full rebuild of the 22re in my 93 pickup. Started as a head gasket job several months ago after overheating in traffic and blowing the head gasket.

Replacing the thermostat I noticed the old one has an extra spring at the end that is missing from the new OEM thermostat (and all 22re thermostats available for purchase that I could find). Curious if anyone knows why they're different (redesign? is the second spring a "2 stage" thermostat? was the old one the wrong thermostat?).