Operation – Cooling system D8 1999 – 2010 (click image to enlarge)
The cooling system is filled as standard with a coolant which does not have to be replaced. This coolant consists of water and 40% anti-freeze (Audi G11V8B). This mixture offers not only sufficient protection against freezing, but also protects the lightweight metal parts of the cooling system against corrosion. This solution also prevents calcification in the cooling system and increases the boiling point of the liquid.
The percentage of anti-freeze should always be at least 40%.
Only Audi G12+ (it’s Pink) or better anti-freeze may be used. Other types of anti-freeze can, in particular, diminish the protection against corrosion significantly. The damage resulting from this can lead to loss of coolant and serious damage to the engine.
If you still have the older blue or purple coolant, it is better to flush your entire system and upgrade to G12+ or better.
Loss of coolant
If coolant loss occurs, the first aspect to be checked is leakage. This should be checked by the manufacturer. Refilling the coolant does not offer a sufficient solution to this problem. If the system is not leaking, then coolant loss can only occur if the engine overheats and the coolant is expelled from the system under pressure.
Topping up coolant
Firstly, switch off the engine and allow it to cool down. Loosen the cap of the expansion tank carefully by rotating it a half revolution and allow the excess pressure to escape. Following this, the cap can be removed completely.
Once this has been done, the cooling system can be re-filled. Never fill the system above the max. marking. Excess coolant will be expelled from the cooling system when the engine is warm.
The coolant tank is located on the right hand side of the motor area, see also the overview of the motor area. The level of the liquid can only be checked when the motor is not running, the level should be between the min. and max. markings when the engine is cold.
It is possible to upgrade the OEM VW/ Audi container to a high pressure aluminium version. It is a little less than 250 Euro’s. The only disadvantage is that it is a little more difficult to top it up being non-transparant.