How to change the oil on a car

Car Engine 1

Never run the engine with little or no oil in it.

The following steps are basic and apply to most types of car or truck engine. An oil and filter change is not difficult, and should be achievable by any confident novice with the right tools. Doing your own oil and filter changes can save a lot of money over paying for a garage to undertake the same work.

You will need

  • A container to catch waste oil – this must have enough capacity to take the oil contents of your car’s sump and be made of a material that will not be attacked by the oil.
  • A set of gloves that are impervious to oil
  • An oil filter removal tool – note that such a tool is not always necessary but will make the job easier.
  • A ring spanner to fit the sump plug

In addition make sure that you have both a new filter AND enough oil to refill your vehicle’s sump and filter. You may also require a new sump plug washer though the old one may be reusable if undamaged and not showing signs of having been squashed and deformed. The oil should be of the type recommended by the manufacturer for the engine; using the wrong type can cause at best increased oil consumption and inefficient running and at worse severe engine wear and degradation.

SEVERE ENGINE DAMAGE WILL RESULT IF YOU ATTEMPT TO RUN THE ENGINE WITH NO OR INADEQUATE OIL IN THE SUMP. 

The manufacturer’s specifications must be followed for your vehicle – overfilling an engine with oil can be as damaging as underfilling it.

Wear suitable gloves when handling engine oil. Used oil has many contaminants in it, and can cause skin irritation and sometimes dermatitis, especially if you have any cuts or abrasions. Oil from an engine that has been running can be hot enough to scald – let a hot engine stand to cool down before starting any work on it. Some components such as catalytic converters and exhaust manifolds can remain very hot for quite some time.

STEP ONE

Park the vehicle on a hard and level surface. If you have access to a vehicle maintenance pit this can be useful, but not essential. If you must raise the vehicle up to gain clearance to get to the sump, the vehicle must be chocked securely. A car jack on its own is insufficient to allow safe access under a vehicle. Ensure that the parking brake is applied and that the vehicle cannot roll. Place the container for the used oil under the sump in a position where it can catch the outflow from the sump plug when it is removed.

STEP TWO

Using the ring spanner, loosen the sump plug. Unscrew it by hand and retrieve it and the sump washer. Leave the oil to drain – this may take more than a few minutes. Whilst the oil drains, clean up the sump plug and decide whether to use a new washer or reuse the old one. Put these items to one side ready for use.

STEP THREE

Taking hold of the oil filter, twist it anti-clockwise to loosen it. It should move by hand, but if it is a little stiff you can use a tool to help. These usually are a strap that loops over the filter that, when tightened, allows more leverage. Once loosened, the filter should unscrew by hand. If it is very stiff then check for damage or other problems carefully before fitting a new filter, as stiffness could be a sign that the thread has been damaged. It is advisable to position the waste oil container where it can catch any oil that leaks from the filter on removal. Be aware that the old filter will be full of old engine oil so care should be taken to hold it and manoeuvre it from the vehicle in a way that doesn’t allow the oil to drip out.

STEP FOUR

On the top of the new filter you will see a black ring seal. Run a small amout of oil over the seal as this will help it seat without leaking. It does not need more than a drop. Line the filter up with the spindle that the old filter came off. It should line up and screw on by hand – do not force it. It might take a couple of attempts to get the thread to pick up. Continue screwing the filter clockwise by hand until it feels tight. It should be hand tight and tools should never be used to tighten it as at best it will be extremely hard to remove at the next filter change, and at worst damage can occur and possibly deformation that will cause leaks.

STEP FIVE

Once the oil from the sump has finished draining (drips may continue for a while – it is not necessary for every last drip to be left to come out) refit the sump plug taking care to ensure that the washer has been applied to it. Tightening the sump plug without the washer can result in leaks and possibly damage to the hole. It may even result in the plug coming loose and falling out when the engine is running. Tighten the plug by hand, taking care not to force it. If it feels hard to tighten this may be an indication that it is cross threading. If this is the case, take it off and try again carefully. It should turn easily until you feel it tighten. Then use the ring spanner to tighten it all the way. Do not overtighten – as a guide it is possible for a right handed person to easily tighten the plug adequately using only their left hand.

STEP SIX

Locate the engine oil filler. This may be combined with the engine breather cap and is usually at the top of the engine, often on the cam cover. Remove the cap, then fill the engine in accordance to the manufacturer’s specifications. Check for any leaks underneath as you fill there should be none, and any leakage will suggest that the filter or sump plug have been incorrectly fitted and must be investigated immediately. Check the oil level on the dipstick. It may take a minute or more for the oil to run through the engine and into the sump so be patient. Once enough oil is in the sump to register at maximum on the dipstick, replace the breather cover and start the engine. The oil pressure warning light may come on briefly on the dashboard. This is normal, and it should go out as soon as the oil filter has refilled itself with fresh oil. If it remains on after a few seconds than stop the engine and check for problems such as leaks.

STEP SEVEN

Check the oil levels again. The level on the dipstick will have dropped because of the amount of oil taken to fill the filter by the engine. This is normal. Top up the sump until the oil is to the maximum mark. Your vehicle is now ready to drive again. Keep the empty container that the new oil came in as this can be used to store the old oil (see step eight).

STEP EIGHT

The used engine oil and filter must be disposed of in accordance with your local authority’s recycling and waste management policies. Used engine oil must NEVER be poured into the ground or down drains. Doing so is a criminal offence in most territories. You may find it helpful to decant the used oil from the container used to catch it into any empty oil containers of the type that the new oil came in.

Photograph courtesy of Mercuryvapour, via Flickr.

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