How-to

How to Check Your Oil Level in a Car

Checking your engine oil is one of the quickest, most important things you can do to keep your car running smoothly. Here is exactly how to do it, and what to look out for.

8 min read·Updated May 2026

Key Takeaway

Park on level ground, wait at least five minutes after switching off, then pull the dipstick, wipe it, reinsert it, and pull again for a clean reading. The oil should sit between the MIN and MAX markers. If it's below MIN, top up before driving further.

Why Checking Your Oil Matters

Engine oil is the lifeblood of your car. It lubricates all the moving parts inside the engine, reduces friction, prevents overheating, and helps flush out dirt and debris. Without enough oil, or with oil that's past its best, your engine can suffer serious damage in a surprisingly short amount of time.

The good news? Checking your oil takes less than five minutes and requires no mechanical knowledge whatsoever. It's one of those simple habits that can save you hundreds, if not thousands, of pounds in repair bills down the line.

If you're looking to buy a used car and want to make sure it's been properly maintained, it's always worth running a vehicle service history check on ServiceStamp before you commit to a purchase.

When Should You Check Your Oil?

Most manufacturers recommend checking your engine oil at least once a month. You should also check it:

Before a long motorway journey.
If your oil warning light comes on.
After you notice your car has been running rough or overheating.
When you collect a used car for the first time.
Shortly before or after a scheduled service.

Pro tip: Get into the habit of checking your oil every time you fill up with petrol. It takes 30 seconds and means you'll never be caught short.

What You'll Need

You don't need any special tools. All you need is:

A clean cloth or paper towel (old rags work perfectly).
A flat, level surface to park on.
Good lighting (a torch is handy if it's dark under the bonnet).
A bottle of the correct engine oil for your car (check your owner's manual).

How to Check Your Oil Level: Step by Step

Follow these steps and you'll have a clear reading in under five minutes.

1. Park on Level Ground

Make sure the car is parked on a flat surface so you get an accurate reading from the dipstick. A slope of even a few degrees can throw the level off.

2. Let the Engine Cool

Turn off the engine and wait at least 5 to 10 minutes. Checking a hot engine gives an inaccurate reading and risks burns.

3. Open the Bonnet

Pull the release lever (usually inside the driver's footwell), then lift the bonnet and prop it open.

4. Find the Dipstick

Look for a brightly coloured loop or handle, usually yellow or orange, near the engine. Pull it out.

5. Wipe and Reinsert

Wipe the dipstick clean with your cloth, push it fully back in, then pull it out again for a clean reading.

6. Read the Level

The oil on the dipstick should sit between the minimum and maximum markers. Anything below minimum needs topping up immediately.

Important Safety Warning

Never check oil on a running engine. Hot oil under pressure can cause serious injury. Always wait for the engine to cool before opening the bonnet.

Reading the Dipstick: What Does It Mean?

The dipstick will have two marks, a minimum (MIN) and maximum (MAX), sometimes indicated by lines, holes, or hatching. Here's how to interpret what you see:

Dipstick Reading Guide

What You See	What to Do
Between MIN and MAX	Your oil level is fine. No action needed.
At or below MIN	Top up immediately. Running on low oil can cause engine damage within minutes.
Above MAX	Overfilling is also a problem. Too much oil can cause foaming and pressure build-up. You may need to drain a small amount.
Black and gritty	It's overdue for a change. This is a sign the oil has reached the end of its useful life.
Milky or creamy	This can indicate coolant is mixing with the oil, possibly due to a blown head gasket. Seek professional advice promptly.

How to Top Up Your Engine Oil

If your oil level is below the minimum mark, here's how to safely top it up:

Check your car's handbook for the correct oil specification (for example, 5W-30 or 5W-40). Using the wrong grade can harm your engine.
Locate the oil filler cap on top of the engine. It usually has an oil can symbol on it.
Remove the cap and place it somewhere safe.
Pour in a small amount of oil, roughly 500ml to start with.
Wait a minute, then recheck the dipstick.
Repeat until the level sits comfortably between MIN and MAX.
Replace the filler cap securely.

Don't overdo it. It's easy to overfill. Add small amounts and check the dipstick each time. You can always add more, but removing excess oil is a much bigger hassle.

Warning Signs to Watch Out For

Between checks, your car will often let you know if something isn't right. Keep an eye (and ear) out for:

The oil warning light. Don't ignore this. Pull over safely as soon as possible and check your level.
A knocking or tapping noise from the engine. Often a sign of insufficient lubrication.
Blue or grey smoke from the exhaust. Could indicate the engine is burning oil.
A burning smell. Oil dripping onto hot engine parts.
Needing to top up frequently. If you're adding oil every few weeks, there may be a leak or internal engine issue worth investigating.

Why a Full Service History Matters

Regularly checking and changing your oil is only worthwhile if it's properly recorded. A documented service history gives you, and any future buyer, proof that the car has been well looked after. It also helps maintain the car's resale value and can make a real difference when it comes to insurance claims or warranty disputes.

When buying used, a car with a full service history is a far safer bet. You can see exactly when oil was last changed, whether services were completed on schedule, and whether any issues were flagged along the way. At ServiceStamp, we make it easy to check a vehicle's complete service record in minutes, so you can buy with confidence.

Frequently Asked Questions

How often should I check my oil?

Once a month is a good rule of thumb, or before any long journey. Many drivers check it every time they fill up with fuel. It only takes a moment.

How do I know which oil to use?

Check your car's owner's manual. The correct oil grade (for example, 5W-30) will be clearly listed. Using the wrong type can cause engine damage over time.

Can I drive with low oil?

You shouldn't. Even short journeys with insufficient oil can cause permanent engine damage. If your oil light comes on, stop safely and check the level before continuing.

How long does engine oil last?

Most modern oils last between 5,000 and 10,000 miles, depending on the oil type and your driving style. Always follow your manufacturer's service intervals.

What if I can't find the dipstick?

Some newer cars don't have a traditional dipstick and instead display oil level electronically via the dashboard. Check your owner's manual for guidance specific to your model.

What does it mean if my oil is dark?

Dark oil simply means it's been doing its job, picking up dirt and combustion particles. Black, gritty oil usually means it's time for an oil change. Light brown or honey-coloured oil is fresh and in good condition.