Originally Posted by
xintersecty
".....So what is the Coolant Circulation Valve? Look at number six in the below diagram. Coolant refers to the engine coolant to cool the engine. When it's run through the cabin heater core, it's actually hot water. There are two valves that allow water to flow through the heater core for the cabin air. Since the heat can be controlled for the passenger and driver there are two valves. ....."
Great write-up and visual aids! Just one clarification, it isn't hot water.
It is the cooling system coolant that circulates through the two section heater core.
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