Volvo 2008 S40 Owner's Manual page 184

Synthetic oil is not used when the oil is changed at the normal maintenance intervals except at owner request and
at additional charge. Please consult a trained and qualified Volvo service technician.
Checking and adding oil
The oil level should be checked every time the vehicle is refueled. This is especially important during the period up to
the first scheduled maintenance service
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.
3. Add oil if necessary. If the level is close to the MIN mark, add approximately 1 US quart (1 liter) of oil.
4. Run the engine until it reaches normal operating temperature.
5. Switch off the engine and wait for at least 10-15 minutes and recheck the oil level. If necessary, add oil until the
level is near the MAX mark.
NOTE
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.
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.