2008 Volvo S40 Owner's Manual - Page 186

Volvo service technician. NOTE Do not top off with water only. This reduces the rust-protective and antifreeze qualities of the coolant and has a lower boiling point. It can also cause damage to the cooling system if it should freeze. Top off with Volvo Genuine Coolant/Antifreeze only (a 50/50 mix of water and antifreeze). 207 09 Maintenance and servicing Fluids CAUTION The cooling system must always be kept filled to the correct level, and the level must be between the MIN and MAX marks. If it is not kept filled, there can be high local temperatures in the engine which could result in damage. Different types of antifreeze/coolant may not be mixed. Check coolant regularly! WARNING Never remove the radiator cap while the engine is warm. Wait until the vehicle cools. If it is necessary to top off the coolant when the engine is warm, unscrew the expansion tank cap slowly so that the overpressure dissipates. Brake fluid The brake fluid should always be between the MIN and MAX marks on the side of the reservoir. Check, without removing the cap, that there is sufficient fluid in the reservoir. Fluid type: DOT 4+ boiling point >536°F (280°C), P/N 9437433 Replace: The fluid should be replaced according to the intervals specified in the Warranty and Service Records Information booklet. When driving under extremely hard conditions (mountain driving, etc), it may be necessary to replace the fluid more often. Consult your Volvo retailer. Always entrust brake fluid changing to a trained and qualified Volvo service technician. Power steering fluid The fluid level is checked at each service interval.