SA-065-22

BULLETIN NOTES
APPLICABLE MODEL(S)/VINS
2016-2021 CX-3 (with coolant control valve)
2017-2023 CX-5 (with coolant control valve)
2018-2021 Mazda6 (with coolant control valve)
2019-2023 Mazda3 (with coolant control valve)
2020-2023 CX-30 (with coolant control valve)
DESCRIPTION
Some vehicles equipped with a coolant control valve may exhibit difficulties when refilling the coolant because the control
valve is closed and air in the engine cannot escape during ignition ON. Therefore, turn the ignition OFF when refilling
engine coolant using the radiator filler neck.
[Reference Information]
1. Remove the cooling system cap (1), then refill the engine coolant (2) using the radiator filler neck until it is close to the
top of the radiator filler neck.
2. The coolant flows into the the engine through the control valve (3) from the upper radiator hose (4).
3. The coolant also flows into the lower radiator hose (5). However, as the control valve (3) is closed during the ignition
ON, air in the engine cannot escape, resulting in difficulty when refilling the coolant.
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Valve position when the valve is open.
(Ignition OFF)
Valve position when the valve is closed.
(Ignition ON)
At the same time when the ignition is OFF, the control valve
is opened and all of the water passages are connected.
At the ignition ON, the water passages are closed.
Water Flow Control
• The PCM adjusts the engine coolant control valve and supplies engine coolant to the appropriate engine coolant
passage according to the changes in the engine coolant temperature.
• By blocking each water passage before the engine warms up and suppressing heat radiation, the temperature of
the internal wall of the cylinder is quickly increased to improve fuel economy.
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