Originally Posted by Decoy_58
make sure your thermostat has a bleed hole in it and install with hole at top
That might be an exercise in frustration, thermostats with a vent hole are out there but they're not common.
That is a good idea however so for the OP, if you can't find one, you can use a 1/8" bit to drill your own. As Decoy said, rotate the thermostat so the vent hole is at the top so it will let any trapped air vent out.
And as said, make sure to install only a 195 degree thermostat and also, as also said, make sure to avoid a fail-safe thermostat.
The first thermostat below shows a factory vent, the second one shows one that was drilled...