How To Change The Oil In Your Car

This is a part of a series of articles provided by the MOT Chelmsford blog.

To many motorists changing the oil in their car is best left to the garage when it needs a service but in reality the task is not as difficult as you might think. First though, it is worth describing what the oil in a car actually does. Basically, it has five functions.

1. Lubrication - An oil film helps keep moving parts from coming into direct contact. This also reduces the amount of energy consumed.

2. Cleaning - The oil traps impurities such as dust and combustion residues which are then deposited in the oil filter. This helps keep the engine clean from build-up.

3. Cooling The Engine - The oil helps to cool the engine parts by dispersing the heat caused by friction.

4. Keeping Water Out - The film of oil helps keep water out. The pistons need good water-tightness for optimum compression and to maintain engine power.

5. Protection Against Rust  - The oil protects internal engine surfaces from rust that occurs from water and combustion acids.

Most car manufacturers advise changing your car oil about every 6,000 miles for normal service but you should check your car manual for the requirements of your particular make of vehicle. This ensures that you always have the optimum levels of oil in your car to do the jobs described above. Too little oil and parts can scrape together with potentially dire consequences. Too much oil and it could spill over. Your filter also needs checking to remove any particles that have built up. Your car should have a dashboard light that comes on if your oil levels are low. Pay attention to this as it could mean that oil is leaking.

You can get your car oil changed professionally by a mechanic at a garage but if you want to save money - why not do it yourself. You should first check your manual so you know where the various parts are. You can then change the oil in four basic steps.

1. Draining The Oil - Almost all cars have space beneath to reach under and change the engine oil but first make sure your engine is turned off and is cool enough to handle. Modern engines run at around 150ÂșC and hot oil can give you a severe burn. Search and locate your drain plug, place a container underneath it and remove the plug in an anti-clockwise direction. You may need an oil filter wrench to do this. When the oil has stopped draining, replace the plug clockwise.

2. Replacing The Filter - Move the oil-catching container under the oil filter. Use the wrench to remove the filter. Then put a thin coat of oil over the new filter and refit. Pay close attention to the instructions as you do not want it to be too loose as the oil could leak out or so tight that you can’t remove it.

3. Adding The New Oil - Locate the oil filler cap and use a funnel to gently pour in the oil. Again check your car manual for how much oil you need. Most have a capacity of 4.5 or 5.5 litres. If you don’t know how much to use, add 4.5 litres, check the oil level and add a bit more if it is too low. Replace the oil filler cap.

4. Checking It Works - Start the engine and make sure that the oil warning light goes off. Look under the car to ensure there are no leaks. Turn off the engine and let it rest. This allows oil to drain down to the crankcase. Then check the oil with a dipstick by inserting it all the way into the oil tank. Remove it after a few seconds to see how far up the oil has covered. Most dipsticks have a ‘minimum’ and ‘maximum’ mark to check by.

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