Porsche 2012 911 GT3 CUP Technical Manual page 16

3.4.3. Cooling fluid
3.4.3.1. Capacity
The cooling system if filled with 11 litres of water and 11 litres of anti-
freeze when delivered. The coolant remains fluid to temperatures of -30°C
in delivery specification with this water/anti-freeze ratio.
For all race events Porsche Motorsport recommends that the factory filled
engine coolant is replaced by 20 litres of water and 2 litres of anti-
corrosion additive (part number. 997.106.907.90), which protects the
water galleries and other cooling system parts from corrosion, reduces
cavitation, lubricates the water pump and increases the boiling point of
the cooling water.
For Cup races supporting Formula 1 events the coolant must be
changes as described below: Approx 20 litres water plus minimum
2 litres anti-corrosion additive part number 997.106.907.90.
Approx 22 litres
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