Yes,it is flowing ,ive loosened lines to bleed any air out. Ive rebuilt alot of these mod j regulators. when i took it apart.i didnt find anything that looked bad.gaskets ,primer valve,primary seat.i flat filed ,it.i thought maybe it had warped between gasket surfaces. It looked fine.Im going to try a new one,and replace the thermostat. whats odd to me, Is that,it freezes in the morning.Then is ok the rest of the day. Kent...Wooten forklift