Most car makers recommend that engine oil is changed and oil filter renewed at 5,000-6,000 mile intervals or every six months.
Oil is drained after removing a plug at the base of the sump. Before beginning, look underneath at the drain plug if it has hexagonal or square recess or squared end, a special tool may be needed to loosen it. Oil flows more readily when hot and is best drained after the engine has been warmed up. The sump is designed to drain when the car is on level ground. If necessary, raising one side of the car a few inches with the jack will provide enough room to reach underneath and loosen the plug, but do not get under the car unless the vehicle is properly supported, lower the jack once the plug is loose.
Use a shallow container to catch the oil. If the sump holds more than five liters, an old washing up bowl will do. Better is an empty 5-litre oil tin laid on its side with a large square hole cut in the upper side. The tin plate is thin enough to cut with an old pair of stout scissors, but be sure to turn over the edges of the metal with pliers. This prevents cutting of fingers when the tin is moved. Purpose made plastic cans are also available.
It is illegal to pour old engine oil down the drain; it should be poured into a container and taken to the nearest local authority rubbish area. A discarded filter can be wrapped in a plastic bag and put in the dustbin. Current practice is to fit a one piece throw away cartridge type filter which screws directly on to the crankcase or on to the filter housing. Earlier engines use bowl type filters which must be dismantled to remove the filter element inside, cleaned, and a new element inserted.
Not all engines have external filters. Volkswagen air-cooled engines have an internal strainer as well as an external filter, some engines also have a centrifugal filter, which is usually incorporated in the crankshaft pulley. These are generally serviced only at long intervals, around 24,000 miles.
HOW TO CHANGE THE ENGINE OIL
We shall be discussing the steps in the process of changing engine oil;
- Warm up the engine by driving the car for about a mile.
- Remove the oil filler cap from the top of the engine to allow the oil to drain more quickly.
- Loosen the drain plug about half a turn.
- Put the container in position and unscrew the plug by hand, ensuring that you do not drop it in the container.
- If the plug is magnetic, wipe off the metal particles that have collected on it with a clean cloth.
- Once the oil has drained, wipe clean the drain plug hole, and refit the plug securely.
- On air-cooled Volkswagen engines, the drain plug plate should be removed and the wire gauze oil strainer underneath cleaned in petrol and dried. Refit the plate using a new gasket, and replace the drain plug.
- On engines with an external, fit a new one.
- Add a little less oil than is necessary to fill the sump. The capacity and grade of oil required will be given by the engine’s manual. In some engines, the oil must be poured slowly to avoid overflowing.
- Take out the dipstick and wipe the end. After allowing the oil a few minutes to reach the sump, check the level. Add oil to the correct level.
HOW TO CHANGE THE CARTRIDGE FILTER
- Although they are fitted hand tight, most cartridge canisters require a strap wrench to loosen them. If you do not have a wrench, one can be made from a pieces of strap wrapped around a socket set extension bar and used to turn the canister. Use a drip tray to catch spilled oil.
- Remove the canister.
- Wipe the sealing face on the block with a clean cloth.
- If necessary, fit the new rubber sealing ring to the flange on the inner end of the new cartridge. Lubricate the ring with a smear of engine oil.
- Screw the filter into position by hand until the ring makes firm contact. Refill the engine with oil, start up and check at the filter for leaks.