I wasn't sure if it was opening in my 1956 buick PROJECT station wagon lol. Well I found an original 56 thermostate in my buick pile of parts .I checked it a pot of boiling water and it opened at 185 so I poped it in. Then drove it up my mountain drive way a couple times to get her hot. The gage read close to 190 and I slowly opened the cap and could actually see the water moving finally. Now to finish the body work. She still seems all over the road and that scares me .I don't know if its the 20 year old tires or if i might have to rebuild the whole front end. I don't want this beast going in a ditch. lol. Bruce.