That's how it should work, they don't open fully right away. But they should open completely with enough heat, if it doesn't you won't get enough flow. Sounds like you tested the new 195* thermostat? Once you swap it in you can check the old one too. Sounds redundant because if the 195 thermostat fixes your problem you know it was the old thermostat, but knowing for s fact that the old one wasn't working right it gives you a little more piece of mind. Plus it's easy enough to do.
