Many drivers who switch to the 2005 Volvo S40 from an older vehicle can become lost when they open the bonnet for their first oil change. The S40 has a special oil filter housing that is inconveniently hidden under some hoses that must first be removed. Worse yet, the filter housing is held in place with an oddly sized plastic cap that must be removed with a socket before you can remove it. Make sure you have your owner's manual on hand to verify what engine variant your S40 has, as the oil capacity varies.
Jack up the front end of the car and place it on jack stands. Make sure you are on a level surface, and that the engine is slightly warm. Remove the plastic skid plate using a 10mm socket. There are three bolts that hold it in place.
Place the oil drain pan under the oil drain plug. Open the bonnet and remove the engine oil cap. Under the car, remove the oil drain plug with a 17mm socket, and allow the oil to completely drain.
Remove the air intake hose with a 10mm socket. There are three bolts that must be removed.
Remove the oil filter housing cap using a 36mm socket. This is made of plastic, so do not use too much pressure or you will crack the housing.
Remove the oil filter and replace it with a new one. Dip your finger in oil and lubricate the new filter's seal. Replace the filter housing cap and the air intake hose.
Clean the drain plug with a rag, and replace it. Replace the plastic skid plate, and lower the car.
Add the correct amount of oil to the engine. The 1.6l engine takes 4 litres, the 1.8l engine takes 4.3 litres, the 2.4l takes 5.8 litres, the 1.6D engine takes 3.7 litres, and the 2.0D engine takes 5.5 litres. Use a funnel to prevent spilling. Replace the oil filler cap.
Volvo recommends using Castrol non-synthetic oil only.