Refilling coolant
When refilling coolant, follow the instructions on the package. Never fill the cooling system with only water. The risk of freezing is increased with too low or too high amounts of coolant.
If there is coolant under the vehicle, smoke from the cooling system, or if more than 2 liters (about 2 quarts) of coolant has been added to the system, there could be something wrong with the cooling system and starting the vehicle could damage the engine. Call a tow truck and do not attempt to start the engine.
Warning
The coolant may be very hot. Never unscrew the cap when the coolant is hot. If coolant must be filled, unscrew the expansion tank cap slowly to relieve overpressure.
![P6-1746-XC40-Refill engine coolant](https://www.volvocars.com/images/support/imgab5b81f61dd86ce9c0a801522e636e41_2_--_--_VOICEpnghigh.png?imwidth=1280)
Unscrew the expansion tank cap and fill coolant as needed. The level should not exceed the MAX mark on the outside of the expansion tank.
Important
- Do not ingest the contents. May cause damage to organs (kidneys).
- Use premixed coolant according to Volvo's recommendations. If concentrated coolant is used, make sure that the coolant mixture is 50% coolant and 50% water of acceptable quality.
- Do not mix different types of coolant.
- To help ensure sufficient corrosion protection in the system, only use new coolant when replacing larger components in the cooling system.
- Never run the engine unless the cooling system is properly filled. An improperly filled cooling system could lead to high temperatures and cracks in the cylinder heads.
- High levels of chlorine, chlorides and other salts may cause corrosion in the cooling system.