Replacing the coolant (Mazda 121 (3))

The coolant must be replaced after repairs to the cooling system components. Replacement is not provided for in the annual maintenance. If the cylinder head, cylinder head gasket, radiator, heater core or the entire engine is replaced during repairs, the coolant must be replaced in each case. This is necessary because anti-corrosion additives act on light alloy components during the running-in process, forming a durable corrosion-resistant layer on them. When adding used coolant, its anti-corrosion properties are already unsatisfactory and on new light alloy components the protective layer may not form or its thickness will be insufficient.

Warning: Coolant is poisonous and must be handled with care - do not pour it down the drain, etc.

Drain

Open the heater valve completely, i.e. move the heater temperature regulator completely into the red area.

Raise and support the vehicle.

If present, remove the lower engine compartment cover.

Unscrew the expansion tank cap.

Precautions: When the engine is hot, place a thick cloth on the plug before opening it to avoid being burned by hot coolant and steam. Open the plug only when the coolant temperature is below 90°C.

Place a container under the radiator to catch the drain.

Open the tap at the bottom of the radiator and drain the coolant. You can use a coin or a large screwdriver to unscrew the tap.

Tighten the drain cock on the radiator to a torque of 20 Nm.

Filling

Prepare a coolant consisting of 50% distilled water and 50% Motorcraft Super Plus 4 antifreeze or another one that meets the Ford ESDM-97B49-A specification and pour it into the expansion tank up to the "MAX" mark.

Start the engine and warm it up for 10 minutes. Accelerate the engine several times to 2500 rpm. When warming up, monitor the coolant level in the expansion tank and, if necessary, top up the coolant.

Close the expansion tank.

Let the engine run until the electric fan comes on. Finally, let the engine run at 2500 rpm for about 10 minutes.

Turn off the engine and let it cool.



Check the coolant level and, if necessary, adjust it. On a warm engine, the coolant level should be at the "MAX" mark, on a cold engine - between the "MAX" and "MIN" marks.

If equipped, install the lower engine compartment cover.