Cooling System: Service and Repair

Bleeding Coolant System And Checking For Water Leaks

Caution: These instructions only apply to vehicles without a latent heat accumulator or independant heating.

Warning: Danger of scalding!

Open sealing cap only after engine has cooled down.

Check cooling system for leaks.
Top up coolant.

To ensure the cooling system is properly vented, it is absolutely essential to follow the steps below:
1. Undo cap but do not remove from expansion tank. This prevents excessive discharge of coolant from the expansion.
2. Turn on ignition.
3. Set heating controller to max. temperature.
4. Set blower to low level. This opens the heating valves and sets the auxillery water pump in operation.
5. Run engine and briefly press accelerator pedal three to four times (approx. 4500 to 5000 rpm) to flush engine cooling cricuit.
6. In doing so, do not run engine for longer then approx. 30 seconds; otherwise coolant will heat up and expand.
7. If the coolant level in the expansion drops in the process, top up the expansion tank to the max. cold fill level.
8. Screw on the cap tightly and allow engine to warm up until the thermostat opens.
9. Check coolant level. Pay attention to differing expansion tank designs.

Transparent Expansion Tank:





Allow engine to cool down before checking coolant level. Coolant tempearture must not exceed 30 deg. C. If ambient temperature exceeds 30 deg. C, allow engine to cool down to at least ambient temperature.
Check coolant level and if necessary top up coolant to max. cold fill level (see marking on expansion tank).

Note: The tank mark indicates the fluid level at approx. 20 deg. C.

Use recommended coolant only.

Black Expansion Tank:





Allow engine to cool down before checking coolant level. Coolant tempearture must not exceed 30 deg. C. If ambient temperature exceeds 30 deg. C, allow engine to cool down to at least ambient temperature.
Check coolant level and if necessary top up coolant to max. cold fill level (the ball on float needle is on the same level as the top edge of the expansion tank).

Note: The tank mark indicates the fluid level at approx. 20 deg. C.

Use recommended coolant only.