To check your engine oil, park on level ground, switch the engine off and let it cool for about 10 to 15 minutes. Open the bonnet, pull out the dipstick, wipe it clean, push it fully back in, then pull it out again and read where the oil sits. It should be between the minimum and maximum marks. If it is on or below the minimum, top up with the grade in your handbook.
That is the whole job in one paragraph, and it takes about five minutes. But getting the reading wrong is easy, and topping up badly can do more harm than running slightly low, so here is how to do it properly – the way I show learners who have just bought their first car and never lifted the bonnet before.
Why checking your oil actually matters
Engine oil keeps all the moving metal inside your engine from grinding itself to bits. Let the level drop too far and those parts run dry, overheat and wear out fast. The RAC puts it bluntly: running low on oil is an easy oversight, but one that can cost thousands of pounds if it leads to lasting engine damage.
Here is what catches new owners out. Plenty of people assume that if they follow the service schedule, they never need to look. Not true. Older engines can develop slow leaks you would never spot, and even modern engines quietly burn a little oil between services. Some cars flash a low-oil warning, but not all do, and you should never rely on it as your only line of defence. A two-minute check every couple of weeks is cheaper than a new engine. And there is a second reason no tyre brand or garage will mention: the driving examiner may ask you about it.
How to check your engine oil, step by step
You need almost nothing: a clean rag or a bit of kitchen roll, and two minutes. Work through it in order.
| Step | What to do | Why it matters |
|---|---|---|
| 1. Park level | Stop on flat ground, handbrake on, engine off | On a slope the oil pools to one side and the reading is wrong |
| 2. Let it settle | Wait 10 to 15 minutes after driving | Gives hot oil time to drain back down, and stops you burning your hand |
| 3. Open the bonnet | Release the catch, prop it safely | You need clear access to the engine bay |
| 4. Find the dipstick | Look for a bright yellow or orange loop, often marked with an oil-can symbol | It is designed to stand out from everything else under there |
| 5. Wipe it clean | Pull it fully out, wipe the metal end with your rag | The first reading is always smeared and useless |
| 6. Reinsert fully | Push it all the way back down until it seats | A half-seated dipstick reads low |
| 7. Read it | Pull it out again and hold it level | The oil film should sit between the two marks |
| 8. Top up if low | Add the correct oil a little at a time, then re-check | Only if it is at or below minimum – see below |
The reading is the bit people rush. Your dipstick has two marks near the tip: a minimum and a maximum. Sometimes they are dots, sometimes short lines, sometimes a little crosshatched box. Where the oil film ends is your level. Halfway between the two is perfectly healthy. If it is sitting on or under the minimum mark, it needs topping up. If it is right up at maximum, leave it alone – you do not want more.
Hold the stick horizontally when you read it so the oil does not run and blur the line, and do it in decent light. On a dark forecourt you can genuinely misread a low level as fine.
Do you check the oil when the engine is hot or cold?
Check it cold, or at least properly cooled down. A cold engine gives you the most accurate, settled reading because all the oil has drained back into the sump where the dipstick measures it.
If you have just been driving, that does not mean you cannot check it – a warm engine is fine, as the RAC confirms. Just wait at least 10 minutes after switching off so the oil has time to run back down and so you do not burn yourself on hot metal. Check straight after a motorway run and the level will read low simply because the oil is still up in the engine, and you might top up when you did not need to. Cold, or 10 to 15 minutes rested, every time.
How often should you check your engine oil?
Get into the habit of checking every couple of weeks, and always before a long journey. The RAC recommends checking once every few weeks, and it is a good routine to tie to something you already do, like filling up with fuel.
Do not confuse checking with changing. Checking the level is the quick dipstick job you do yourself. Changing the oil is a full drain and refill done at a service, and most manufacturers set that for every 12 months or a set mileage, whichever comes first (some modern cars stretch to two years). Your handbook or service light tells you when a change is due. But between changes you still check the level yourself, because that is how you catch a slow leak or a thirsty engine before it becomes a breakdown.
The “tell me” question examiners ask about oil
Here is the driving-test angle almost no maintenance guide mentions. Checking your oil is part of the practical test.
Before you drive off, the DVSA examiner asks you one “tell me” safety question from a set list, and one of them is about engine oil. The official wording is: “Open the bonnet, identify where you would check the engine oil level and tell me how you would check that the engine has sufficient oil.” You explain it out loud and point to the dipstick. A clean answer is something like: “I’d check the dipstick with the car on level ground and the engine off, making sure the oil sits between the minimum and maximum marks, and top it up through the filler cap if it’s low.”
If you can already do the real thing, saying it is easy. We list all of these in our full show me, tell me questions and answers guide, and it is one of the first bits of car familiarity a good instructor builds in – the sort of confidence we develop from your very first driving lesson, so nothing on test day feels like a surprise.
How to top up your oil (and not overdo it)
If the level is low, topping up is straightforward, but this is where beginners cause damage, so go gently.
- Get the right oil. Your handbook lists the exact grade and viscosity for your engine, written as something like 5W-30. That code is not decoration – the engine is designed around a specific thickness. Using the wrong grade, or an approximate one, can affect how well it protects the engine, and if your car is under warranty, the wrong oil can invalidate it. When in doubt, check the handbook or ask the manufacturer.
- Find the filler cap. This is on top of the engine and carries the same oil-can symbol as the dipstick. It is a separate cap from where you check – do not pour down the dipstick tube.
- Add a little at a time. Pour in a small amount, maybe a quarter of the way towards the mark, using a funnel to avoid spills. Give it a minute to drain down.
- Re-check with the dipstick. Wipe, reinsert, read again. Repeat until you are safely between min and max. Creeping up on it slowly is the whole trick.
- Cap up and tidy. Refit the filler cap and the dipstick firmly, wipe any spills off the engine so they do not smoke, and close the bonnet.
Is it worse to overfill or underfill oil?
Both are bad, and this is why you top up slowly rather than emptying the bottle in. Underfilling starves the engine of lubrication. Overfilling is arguably sneakier: too much oil can be churned by the crankshaft into a froth full of air bubbles, which then cannot lubricate properly – so you can damage an engine by giving it too much, not just too little. If you badly overfill, do not drive; have the excess drained. The safe zone is exactly that, a zone between the two marks, and your only job is to land inside it.
What does the oil colour tell you?
Fresh oil straight from the bottle is a clear, golden colour, a bit like syrup. Once it has been in a working engine for a while it turns dark brown, and that alarms a lot of first-time owners. It is completely normal – the oil darkens because it is repeatedly heated and cooled, as the RAC explains, and dark brown does not mean anything is wrong.
Healthy oil is amber to light brown and slightly see-through on the dipstick. Reach for a change, or a garage, if the oil is jet black and thick, gritty between your fingers, milky or foamy (which can hint at coolant mixing in), or smells strongly of burnt fuel. Colour is a rough guide, not a science, but a quick glance every time you check does no harm.
What are the signs your oil is low?
Ideally you catch a low level with the dipstick long before the car complains. But the warning signs of genuinely low oil, roughly in the order you notice them, are:
- The oil warning light or a “low oil” message on the dashboard – treat this as urgent, not a suggestion.
- A ticking or knocking from the engine, often loudest on start-up or under acceleration, as dry parts rattle.
- Rising engine temperature on the gauge, because oil helps carry heat away.
- A burning or oily smell, sometimes with light smoke, which can point to oil leaking onto hot parts.
- Rougher running – sluggish response or worse fuel economy.
If the oil pressure light comes on while you are driving, that is the serious one. Pull over safely as soon as you can and switch off – keep running an engine with no oil pressure and you can wreck it in minutes.
Frequently asked questions
Do you check the oil when the car is hot or cold?
Cold is best, because the oil has fully drained back into the sump and gives the truest reading. A warm engine is acceptable, but wait at least 10 minutes after switching off so the oil settles and you avoid burning yourself. Checking straight after driving reads artificially low.
How often should I check my engine oil?
Every couple of weeks is a sensible routine, and always before a long trip. The RAC suggests once every few weeks. That is separate from an oil change, which most manufacturers set for every 12 months or a set mileage, whichever comes first.
Can I drive if my engine oil is low?
If it is slightly below the minimum, top it up before any real distance and you are fine. If the dashboard oil pressure warning light is on, stop as soon as it is safe and switch off – driving on with no oil pressure risks serious, expensive engine damage. When you are unsure, check the level before you set off rather than after.
Is it normal to top up engine oil every month?
An occasional small top-up between services is normal, especially in older or higher-mileage cars that burn a little oil. Needing to add a noticeable amount every month, though, suggests a leak or a bigger issue worth having a garage look at, rather than something to keep quietly topping up.
Is it worse to overfill or underfill oil?
Both cause harm. Underfilling starves the engine of lubrication; overfilling lets the crankshaft whip the oil into a froth that cannot lubricate properly and can build damaging pressure. Add oil a little at a time and re-check, aiming to land between the minimum and maximum marks.
What colour should healthy engine oil be?
Amber to light brown and slightly translucent on the dipstick. Fresh oil is golden; it naturally darkens to brown in use, which is normal. Jet-black, thick, gritty, milky or burnt-smelling oil is a sign it is due for a change or a professional look.
The confidence that comes with knowing your car
Checking your oil is a five-minute habit, but it is really the first step into understanding the car you drive rather than just steering it. That quiet confidence – knowing where the dipstick lives, what a healthy level looks like, why the examiner asks – is what turns a nervous learner into a capable driver.
It is also what we build into every course. Our Provisional intensive course suits learners who are close to test-ready and want to polish the practical skills and car know-how that make test day feel routine, and you can see the whole approach on our how it works page. Still weighing up the options? Our guide to what an intensive driving course costs lays out the numbers, and once you have passed, the Pass Plus scheme is a smart next step for real-road confidence.
Ready to get properly test-ready with instructors who teach the whole car, not just the pedals? Book your course today and let us get you there.