The oil in your car is the lubricant that keeps the parts working smoothly and helps to keep them cool. Without it, your car will eventually tear itself apart. We’re going to look at what oil does, why you need to change it and how to do just that. 

What Does Car Engine Oil Do? 

Chances are you wouldn’t try to fry an egg without putting some sort of oil in the pan first. This oil helps to stop the egg from sticking to the pan and burning into an inedible mess. The same principles apply to your car’s engine. 

The internal workings of your engine contain lots of moving parts that all need to work closely together at high speeds and for long periods of time. In order to do this without breaking or overheating, you need to add the correct type of oil.

The number one way to keep your car running well for years of trouble-free motoring is by changing your oil and oil filters regularly. It doesn’t guarantee that other parts of your car will break down, but clean oil will certainly help. 

Engine oil lubrication system

Different Kinds of Oil

All car oils are the same, right? Then why are there racks of different oils at car repair shops? The answer is that different engines need different types of oil to run at their best. Let’s look at the different types you might come across:

The main difference in oils is viscosity. When something is viscous, it’s sticky and thick, sort of like golden syrup. The level of viscosity in car oil affects its resistance to flow inside your engine. Depending on your engine type, using the right oil will improve your fuel efficiency and even give you more horsepower.

Oils are rated from 0, the lowest viscosity, to 60, the thickest. This information is displayed on the side of oil bottles usually looks something like 10W30. The 10 stands for the lowest optimum operating temperature, and the 30 stands for the highest, and the “W” stands for winter.

Knowing the ins and outs of oil types isn’t all that important but using the right oil for you make and model is vital. Don’t listen to know-alls who’ll tell you that you get better performance from lower viscosity oils.

 Car manufacturers design engines with specific oils in mind, so save yourself trouble in the future by sticking to what’s in your service manual. 

Which engine oil to choose

Why Should You Change Your Oil?

You will have heard before that changing your oil regularly is a good thing, in fact we think it’s one of the best ways to make sure your car lasts for hundreds of thousands of miles. But why are oil changes so important?

The inside of your engine is a hot place to work. Your engine oil must work at high temperatures and for long periods of time and live outside with your car exposed to the elements. Simply put, your oil is the lifeblood of your engine- it rushes around the moving parts and keeps them from rubbing together. 

Over time though, condensation can form inside parts of your engine and this added water works to break down your clean oil into a black, sticky mess. The thicker it gets, the higher the viscosity, and the harder your engine is forced to work. 

Protective varnish and small pieces of metal can wear off moving parts during use. These fragments get trapped in your oil system and eventually work like bits of grit in a sandblaster to wear out seals and passages. 

The only way to fix the problems associated with broken down oil and gunk in your engine is to swap out your oil before they have a chance to take hold in the first place. 

What Intervals Are Recommended?

Manufacturers guidelines vary between makes and models, so always consult your service manual or owner’s forum for the oil change intervals that suit your own vehicle. We think you should change your oil depending on how much you drive your car though, so it’s not always an easy answer. 

Modern cars using fully synthetic oils probably only need changing every 5-10,000 miles, but this depends on how you use your car, and what sort of miles you do. Not only that, but the type of car you drive will influence your oil change intervals. Vehicles like vans, pickups and performance cars will need regular maintenance because they work that much harder than, say, a domestic hatchback.

Engines are happiest when they’re up to temperature and working at an even pace, so getting stuck in traffic all the time is bad for your car. Urban driving causes more extreme wear because of these frequent stops and starts.

Urban commuters should check and change their oil more frequently than someone who drives long motorway miles, even though their mileage will be much higher. The same goes for a driver who often loads their car up with heavy gear and tows a trailer. The extra wind resistance and weight will force their engine to work harder and break down oil more quickly.

You might not think it makes much of a difference, but slow drivers need to change their oil more often than those of us who drive to the limit on roads and motorways. Although putting your foot down will wear out an engine over time, not making your engine work will cause just as much damage. 

The real way to know the correct oil change intervals for your car is to check your oil frequently and bear in mind what type of driving you do. And if in doubt, talk to a trusted mechanic.

Checking Engine Oil Level

What Happens If Your Oil Light Comes On?

The little oil can symbol on your dashboard will light up when you switch on your ignition, and that’s normal. If it stays on however, you might have a problem. The light is connected to your car’s computer, which gets its information from sensors inside your engine. 

The oil can symbol flicks on most commonly when your oil pressure is incorrect. Usually it’s because it’s low, but if you’ overfilled your oil it will trigger as well. It’s not a good idea to drive your car if the oil light is on, because it means your engine is not properly lubricated and can overheat or war out quickly. 

Engine Oil warning light

Changing Your Oil

Regular oil changes are a great idea, but if you’re always going to a garage for it, it’ll start to cost you a lot of money in the long term. Changing your own oil is easy and can be done on your driveway with a few basic tools. We’re going to show you how:

What you’ll need

  • Rubber gloves and eye protection
  • A car jack and axle stands
  • A socket set that fits your car
  • An oil pan or suitable container to catch the old oil
  • New oil that is suitable for your car
  • A new drain plug gasket if it needs it
  • A new, quality oil filter

A step-by-step guide to changing your engine oil

  • Park your car on a flat surface and make sure the handbrake’s on
  • Run your engine for a few minutes to warm up the oil, then switch off to cool it a bit
  • Jack up your front end and place the axle stands where they can safely take the weight
  • Lower the car onto the axle stands and remove your jack
  • Place the oil pan under your drain plug to catch the dirty oil
  • Using your socket wrench, start to undo the drain plug but don’t take it all the way off
  • Put on your gloves and undo the plug the rest of the way so the oil drains into the pan
  • As the oil drains out, inspect the drain plug and replace the gasket if it needs it
  • When the oil has stopped dripping, replace the oil plug firmly
  • Place your oil pan under the oil filter and unscrew it all the way off
  • As the oil drips out, rub a little new oil around the new filter gasket to help it seal
  • Screw the new filter on so that it fits snugly
  • Jack your car back up, remove the axle stands and let it down again
  • Open the oil filler cap on your engine and refill you oil until it’s full on your dipstick
  • Safely dispose of your old oil at your local garage or recycling centre

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