How to check car fluid levels

Checking the fluid levels in your car is essential to ensure it’s ready for the road. The engine oil, coolant, brake fluid, and washer fluid all play important roles in keeping your car operating smoothly and safely, so keeping them topped up is vital. The good news is that checking car fluid levels is easy and should only take a few minutes.

Learn how to check your car's fluid levels, including engine oil, coolant, brake fluid, and windscreen washer fluid, with our expert guide.

Your car’s drive belt transfers power from the engine to several critical components, including the power steering, air conditioning compressor, alternator, cooling fan and water pump.

The drive belt is a long, supple, and strong belt that flows around the engine. Often, one side is flat, while the other is tapered or ribbed to provide grip.

Over time, the belt can wear out, causing a squeaking sound which can spell danger. Even if it’s still working fine, the drive belt in your car should be replaced around every 60,000 miles.

• Engine oil: Your car’s engine oil circulates around the engine, keeping all the moving parts lubricated and reducing friction. Over time, dirt and debris will become suspended in the oil and deposited in the oil filter. Regular oil and filter changes are crucial to the health of your engine.
• Coolant: Your car’s coolant helps to keep your engine operating at the optimum temperature, helping to prevent corrosion inside your cooling system and freezing in the winter.
• Brake fluid: Brake fluid transmits the pressure on the brake pedal through the hydraulic system, including the brake callipers and pads.
• Windscreen washer fluid: Windscreen washer fluid keeps your windscreen clear of dirt and debris, giving you a clear view of the road ahead.

You should check your fluid levels weekly. Building it into your weekly routine will ensure you spot any dangerous drops, leaks, or spills before they get worse.

Under the car bonnet, the visual indicators like the minimum and maximum fill lines make it clear to see if your fluid levels have dropped.

Don’t worry if you find you need to top up your fluids. It’s normal for engine oil, brake fluid, and coolant levels to drop over time. However, sudden loss of fluids can indicate an underlying issue. If you’re worried about your fluid levels take your car to your local Halfords garage and one of our experts can take a look.

You won’t need any special tools to check the fluid levels in your car, but you will need some gloves and a rag or tissue. You may find it useful to have a torch ready if the light is low.

To check all the fluids in this guide, you’ll need to lift your car bonnet. The engine bay and engine can get hot, so be careful when lifting the bonnet and touching anything.

You should be especially careful when checking the engine oil and coolant levels, as these fluids operate under pressure and at high temperatures.

Checking the engine oil level is an essential car maintenance task that everyone should know how to do. It’s simple, easy, and should take a few minutes.

Check the engine oil level before you start the car or wait a few minutes after switching off the engine. This will ensure an accurate reading and that the oil has cooled down and can be handled.

Here’s a step-by-step guide to checking your engine oil level:

• Find the engine oil dipstick. The dipstick will be located somewhere on your car’s engine. (The location varies on different vehicles, so check your handbook if it’s not clear to you.)
• Pull out the dipstick and wipe the end with a clean rag or paper towel to clean off the oil.
• Insert the clean dipstick all the way back into the tube and pull it out once more.
• Check the engine oil level. You should now see the oil level clearly on the end of the dipstick. It should be between the lower min and upper max markings.

If your oil level is on or below the minimum, you’ll need to top it up. It’s important to use the right engine oil for your car. You can find details in your handbook or use Halfords’ engine oil finder.

To top up the oil, use a funnel and pour the oil slowly into the engine, a little at a time. Wait a few minutes for the oil to work through the engine and test the level again. Keep adding oil until you reach the top indicator. Avoid overfilling, as this could damage the engine.

An engine oil check is an important part of preventative maintenance and something you should do every week. It’s especially important to check the oil level before setting off on long journeys.

If you consistently experience low engine oil levels, there could be wear to the engine, including seals, defective gaskets, worn piston rings or valve guides.

Other warning signs include water droplets in the oil, a milky substance by the cap, or dirt and debris in the oil. These are all signs that something isn’t right with your engine and it needs expert attention. Book an appointment and speak to one of our experts if you suspect an issue.

Engine coolant (often called antifreeze) works hard to keep your car’s engine at the right operating temperature. If the coolant level gets too low, it could cause your engine to overheat – leading to an expensive failure.

Here’s a step-by-step guide to checking engine coolant levels:

• Inside your car’s engine bay, you’ll see a coolant reservoir. The liquid inside could be green (ethylene glycol antifreeze), orange, or red (silicone-free antifreeze).
• You’ll see upper and lower markings on the reservoir. The correct level will be to the upper end of these two markings.

The coolant level can rise and fall depending on its temperature, but if your engine coolant level is low, you must top it up.

You should only ever remove the coolant reservoir cap when the engine is cool. A hot cooling system will be pressurised, so removing the cap when the engine is hot can lead to serious injury. You should use a glove to remove the reservoir cap. Add the coolant and check it’s at the right level. Next, drive the car for five minutes and visually recheck the coolant level to ensure you’ve added enough.

Always use the right antifreeze for your car, and try not to mix them. In an emergency, you can add water to the coolant tank. Be warned that this will dilute the mixture and is only a temporary solution.

If the coolant level regularly falls, you could have a leak in the cooling system. Components such as hoses, the reservoir cap, drain plug, thermostat housing and water pump are all areas to check for leaks.

If the coolant in the reservoir looks brown or rust-coloured, the system should be drained, flushed, and refilled – a job for a professional.

Brake fluid is critical in your car and should be checked regularly. Low brake fluid is an MOT failure, so always check before you take your car in for its annual check.

While the system is sealed, brake fluid will still absorb moisture from the air over time, causing degradation of the fluid. This can reduce the effectiveness of your brakes.

Here’s how to check your car’s brake fluid level:

• You'll find the brake fluid reservoir underneath the bonnet. It’s usually on the driver's side of the engine compartment. The brake fluid filler cap should have a helpful icon that will help you identify it.
• You may need to wipe the brake fluid reservoir with a cloth if it’s oily or dirty.
• Once clean, you can now check if the fluid level is between the maximum and minimum lines (or full indicator) on the side of the reservoir.

Brake fluid at the minimum or below spells danger, so it’s important to top it up immediately. Always use the right type of fluid because mixing different types can cause brake failure. You can find the correct brake fluid in your car’s handbook or by using our brake fluid finder tool.

Top up your brake fluid by adding the fluid to the reservoir, using a funnel until it reaches the right level.

After filling the reservoir to the proper level, put the cap back on, reattach the sensor plug, and ensure the cap is fully seated to prevent fluid leakage or contamination.

It’s normal for the brake fluid level to fall slightly, caused by the natural wear of the brake pad linings. However, if you experience consistently low levels or see rust deposits, dirt particles, or water droplets in the fluid, book it in for a professional check. Changing the brake fluid is a complicated task that’s best left to the professionals.

Washer fluid may not seem as important as the other fluids listed above, but having clear visibility is vital. Low washer fluid could lead to an MOT failure, so keeping it topped up is important.

The first sign your washer fluid is running low is that nothing happens when you pull the lever or press the button in your car. If that happens, it’s time for a top-up.

• Lift the bonnet and look for a blue cap. This is the top of your windscreen washer fluid reservoir.
• There are no fill levels here - just check that there is liquid in there. If there is, you’re fine to drive.

If the windscreen washer fluid reservoir is low or empty, it’s time for a refill. Topping up the fluid reservoir is as simple as lifting the cap and adding the fluid – but don’t be tempted to add water on its own. Use a specialist ready-to-use or diluted concentrated screen wash and fill the reservoir to the top to provide the best cleaning power and protection.

Alongside all-purpose screen wash, you can find specialist products that work in cold temperatures, making them perfect for the winter.

You can find all the right fluids for your vehicle on our website by simply entering your vehicle registration.