Replacing the coolant (VW Polo 4)

If the coolant was drained during repair of the engine cooling system, it must be replaced. Coolant replacement is not provided for in the maintenance. If the cylinder head, cylinder head gasket, radiator, heat exchanger or the engine itself were replaced during repair, the coolant must be replaced in each case. This is necessary because during the circulation process, anti-corrosion additives are deposited on new light metal parts and thus form a durable anti-corrosion layer. The anti-corrosion additive in the used coolant is usually no longer sufficient to form a sufficient protective layer on new parts.

Warning: Coolant is quite toxic. District and city administrations provide information on how to dispose of coolant.

Draining the coolant

Remove the lower engine compartment cover.

Safety instructions

When the engine is hot, before removing the expansion tank cap, place a thick cloth on it to avoid scalding with hot liquid or steam. Remove the cap only at temperatures below +90°C.

Open the expansion tank cap.

Place a clean container under the radiator to drain the coolant.



Unscrew the drain plug and drain the coolant completely into a container. Then screw the drain plug back in.





Diesel engine with a working volume of 1.4 l: drain the coolant from the cylinder block. To do this, disconnect the coolant hoses "arrows" at the oil cooler and collect the remaining coolant in a drain container. Then immediately reconnect the coolant hoses and secure with spring clamps.

1.9L diesel engine: Disconnect only the lower coolant hose -left arrow- at the oil cooler and drain the coolant. Then immediately reconnect the coolant hose and secure with a spring clamp.

Pouring coolant

Prepare a coolant in the proportion of 50% drinking water and 50% VW/SEAT antifreeze.

Remove the lower engine compartment cover.

Lower the car.



Pour coolant through the hole in the expansion tank up to the MAX mark.

Bleeding air from the cooling system

Close the expansion tank cap.

Set the heating system regulator in the passenger compartment to the kalt (cold) position.

Start the engine and maintain the engine speed at 2000 rpm for approximately three minutes.

Continue warming up the engine at idle speed until the cooling system fan turns on.

Safety instructions

When the engine is hot, before removing the expansion tank cap, place a thick cloth on it to avoid scalding with hot liquid or steam. Remove the cap only at temperatures below +90°C.

Check and, if necessary, top up the coolant level to the MAX mark.

When the engine is warmed up to operating temperature, the coolant level should reach the MAX mark, and when the engine is cold, it should be between the MAX and MIN marks.

Stop the engine.