Mazda CX-5 Service & Repair Manual: Cooling System Cap

Purpose, Function

• The cooling system cap maintains appropriate pressure in the engine coolant passage. In addition, cooling efficiency has been improved by increasing the engine coolant boiling point.

Construction

• The cooling system cap is installed to the upper part of the radiator.

  

  
  

Operation

When engine coolant temperature is high

1. When the engine coolant temperature is high, the pressure in the engine coolant passage increases and the pressure valve is pressed and opened.

2. Engine coolant flows into the coolant reserve tank when the pressure valve is open.

When engine coolant temperature is low

1. When the engine coolant temperature is low, the pressure in the engine coolant passage decreases and the vacuum valve is opened.

2. Engine coolant in the coolant reserve tank flows into the engine coolant passage when the vacuum valve is open.