Subaru EJ 22 Cooling System

[Scott Hogan]

My RAF got a new radiator late last year, and at the same time I

[Dewie]

The change in operating temperatures and pressures is due to the smaller volume of water and a reduction in cooling area when the heater core is removed. And yes the heater circuit is the cooling system bypass circuit, the only way the engine can be run without a bypass of some kind is to remove the thermostat.