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How to check and top up your oil

Easy ways to keep your car's engine oil running smoothly

Checking and topping up your engine oil is one of the most important car maintenance tasks. But it's also one of the simplest to do by yourself.

Your car's annual service will include draining the old oil, replacing the oil filter and re-filling with new oil, but checking your oil and topping it up if necessary between services can be done in minutes. Keep your oil level topped up and you could avoid engine trouble down the line too.

How to check your engine oil level

  • Check your car's parked on level ground, that the engine's cool and that you've got some of the correct oil for your engine in case you need to add some.
  • Open the car's bonnet and refer to your owner's handbook to find the dipstick. Some newer cars have electronic oil monitors and don't have traditional dipsticks for manual inspection.
  • Once you've found the dipstick, remove it, and wipe it clean with a bit of kitchen towel.
  • You'll see two marks on the clean dipstick for maximum and minimum oil levels. A litre of oil is the approximate difference between these two marks. 
  • Replace the clean dipstick and push it all the way back into its tube.
  • Pull it back out, and this time look at both sides of the dipstick to see where the oil level is.

How to read your oil dipstick

  • If the top of the oil 'streak' is between the two marks, the level is fine.
  • If the oil level is below halfway between the marks then we would recommend adding some.
  • If it's close to or even below the minimum mark then you definitely need to add some oil.

How to find out which oil your car needs

Using the wrong oil can damage your engine, so check your car's handbook to see the best oil to use for your car. It's important to use oil that meets the right technical specifications (ACEA, API, VW, etc) as well as the right grade - that's the two numbers separated by a 'w', such as 5w30.

If you don't have a handbook, a quick Google search should help you. Shell and Mobil have oil matching services on their sites.

You’ll either need your registration, or the make, model, year, engine and fuel information for your car.

How to top up your engine oil

  • Find the oil filler cap in your engine bay. This should have the word ‘oil’ marked on it, or an outline of an oil can.
  • Using a funnel, carefully pour your oil in.
  • If you don't know how much you'll need, it's important to only add a little at a time, wait a bit to let it run down to into the bottom of the engine and then recheck the level on the dipstick. As a rough guide, for most cars it should take around a litre of oil to raise the level from the minimum to the maximum mark.
  • Pour in a little at a time, and check the oil level by reinserting the dipstick

Should I check my oil when the engine is hot or cold?

Ideally, your engine should be cool. If you've just been driving your car, wait 5-10 minutes after you've parked to check your oil level, or check it first thing before you use the car. This is so you get an accurate reading and don't burn yourself on any hot car parts.

What colour should my engine oil be?

New oil is clean and golden in colour, but quickly turns dark brown or even black when it's in use. This darkening is quite normal.

Oil with a milky or foamy appearance indicates a cooling system problem - coolant is leaking into the oil.

Should my car be running when I'm adding oil?

No. Your engine should be off whenever you're checking anything under the bonnet, including checking your oil level and topping up your oil.

What happens if I run out of oil?

If the oil level drops too far it will affect the oil pump's ability to pick up and circulate oil around your engine from the sump - you might see the oil pressure warning light come on when you're cornering.

With low oil pressure, the oil's less able to lubricate the bearings and other moving parts. Metal runs on metal, quickly causing irreversible and expensive damage.

How long does engine oil last?

It depends to some extent on the car and how it's driven, and your handbook will tell you the manufacturer's recommended oil change interval.

Most cars are on fixed interval servicing with, for example, the oil changed every 9,000 miles or 12 months, whichever comes first.

Some cars are on variable servicing intervals, in which case the car will tell you when an oil service us due based on how it's been driven and the condition of the oil. If your car's on variable servicing then the recommended oil will be specially formulated for extended drain intervals.

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