Topping up the coolantTopping up the coolant  - Cooling system - Checking and topping up fluids - General maintenance - Audi S5 Owner's Manual - Audi S5

Be careful when topping up coolant.

Switch off the engine.
Wait for the engine to cool down.
Cover the cap on the expansion tank ⇒ fig. 215 with a cloth, and carefully unscrew the cap anti-clockwise ⇒  Add coolant..
Add coolant.
Screw the cap on again tightly.

Make sure that the coolant meets the required specifications ⇒ Coolant. Do not use a different type of additive if antifreeze additive G12+, G12 or G11 is not available. In this case use only water and bring the coolant concentration back up to the correct level as soon as possible by putting in the specified additive.

Always top up with fresh, unused coolant.

Do not fill above the MAX mark. Excess coolant is forced out of the system through the valve in the filler cap when the engine gets hot.

If a lot of coolant has been lost, wait for the engine to cool down before putting in cold coolant. Failure to do so could result in serious engine damage.

The cooling system is under pressure. Do not unscrew the cap on the expansion tank when the engine is hot: you could be scalded by escaping steam
The coolant and coolant additive can be a health hazard. Store the coolant additive in the original container in a safe place out of reach of children risk of poisoning.

For the sake of the environment
Drained off coolant should not be used again. Drain off the used coolant into a suitable container and dispose of it in the proper manner (observe environmental regulations).