Volvo 2007 S80 Owner's Manual page 187

Not checking the oil level regularly can result in serious engine damage if the oil level becomes too low.
Oil that is lower than the specified quality can damage the engine.
Volvo does not recommend the use of oil additives.
Always add oil of the same type and viscosity as already used.
Never fill oil above the MAX mark. This could cause an increase in oil consumption.
Checking and adding oil
NOTE
Before checking the oil:
The car should be parked on a level surface when the oil is checked.
If the engine is warm, wait for at least 10-15 minutes after the engine has been switched off before checking the
oil.
Checking the oil
1. Pull out the dipstick and wipe it with a lint-free rag.
2. Reinsert the dipstick, pull it out, and check the oil level. The level must be between the MIN and MAX marks.
3. Add oil if necessary. If the level is close to the MIN mark, add approximately 0.5 US quarts (0.5 liters) of oil.
4. Recheck the level and add more oil if necessary until the level is near the MAX mark.
195
06 Maintenance and specifications
Engine oil