This morning I got to thinking how easy it was to fix my cars from the 60s/70s, the stat is stuck open on my vec, and needed to do a 100 mile round trip, so I sploshed a pint of very hot water on my stat,, and it worked, did the 100 miles with temp guage only 2 degrees under my summer reading and a nice toasty car,

WARNING, I am only telling you what worked for me. do this at your own risk.