Self-service: How to check fluid levels in your car

Self-service: How to check fluid levels in your car

Checking fluid levels on a regular basis is an important part of car maintenance, as they each play a vital role in keeping your car in working order. These regular and simple checks could help you save money on unexpected costs during an MOT or service, and help you avoid unwanted breakdowns.

We’ve put together a simple guide for finding and checking the levels of each important fluid reservoir under the bonnet. Before checking any fluids, ensure the engine is turned off and has completely cooled down (unless stated).

Firstly, we’ve established which symbols to find on the caps for each fluid, however you should refer to your vehicle manual if unsure about where these reservoirs are, or if there’s a slightly different symbol.

Which Fluids Should I Be Checking

1. Engine Oil

Oil Pressure Loss

An engine lacking oil will cause components to grind against each other and could eventually wear them out, so it’s important to check levels for the engine components to run smoothly. To check oil levels:

  • Find the dipstick located by the engine, or check the manual if unsure.
  • Pull out the dipstick and clean it with a cloth, then put it back into the oil.
  • Pull the dipstick out again and note the oil level - it should sit between the upper and lower levels marks. If the oil level is closer to the lower mark, top up.
  • Put the dipstick back into the pipe and secure it.

If a top up is required, check the manual for which oil is required, and to locate the oil cap if unable to spot. To top up, find the oil cap on top of the engine and pour in some oil, but don’t top up too much - add a bit at a time and repeat process above to avoid spilling. Take the car to the garage if top ups are frequent.

2. Engine Coolant

Temperature Warning

It’s important to keep an eye on coolant (also known as anti-freeze) and water levels in the radiator, as these help to cool down the engine. An inefficient cooling system is likely to cause unnecessary and expensive damage to the vehicle’s engine. When checking the coolant:

  • Clean the top of the reservoir, so dirt can’t get in the fluid, then open the top.
  • Fluid levels should sit within a half inch of the top, if this isn’t the case top up with brake fluid.
  • If the fluid is dark in colour, or the brake fluid is empty, take the vehicle to the garage.

3. Brake Fluid

Handbrake Warning

When you put your foot down on the brake pedal, the brake fluid moves through the brake lines to the front and back brakes of the vehicle. If air gets in the brake lines, your vehicle may be unable to stop properly. To check the fluid levels:

  • Clean the top of the reservoir, so dirt can’t get in the fluid, then open the top.
  • Fluid levels should sit within a half inch of the top, if this isn’t the case top up with brake fluid.
  • If the fluid is dark in colour, or the brake fluid is empty, take the vehicle to the garage.

Brake fluid is very toxic, so any clothes with it on should be disposed of; brake fluid also eats paintwork, so if you spill onto the body, wipe and dispose of quickly. Avoid getting grease of oil in the reservoir as it’ll damage the braking system.

If a vehicles brake pads aren’t functioning properly, it could lead to an accident, so check fluids and the conditions of brake pads, especially before long journeys.

4. Screenwash Fluid

Windscreen Washer Fluid Level

This fluid is used by the driver to clean the windscreen for a clear view of the road. The DVSA’s study found that 6.6% of MOT failures are due to faulty windscreen wipers and washers1, so this check should be done regularly.

  • Locate the screenwash filler cap by finding the symbol on the top and take it off.
  • Top up with screenwash fluid. If you can’t see how full the reservoir is, top it up a little bit at a time to avoid spillage.
  • You shouldn’t mistake engine anti-freeze for screenwash as it can damage the paint.
  • Water and washing-up liquid should be avoided as the salt can also damage paint work.

It’s the law that all road cars must have functioning windscreen wipers and washers2, so you should check fluid levels regularly – especially if used often. The fluid can be bought at most garages, petrol stations and supermarkets.

5. Power Steering Fluid

Power Steering Fluid Level

Most vehicles will have power steering, which allows the driver to steer the wheels with little effort, by pumping pressurised steering fluid through a piston on part of the front wheels. Therefore, it’s important the reservoir is checked regularly and topped up when necessary.

  • Locate the power steering fluid reservoir (refer to manual if unsure). If the tank is see-through, use the min and max levels on the side to judge how much is in there.
  • If the liquid can’t be seen through the tank, use a dipstick which is usually attached to the cap. The dipstick may have “hot”, “cold” and “add” along it, for checking after the engine’s been on.
  • Good fluid is usually clear, or amber or pinkish in colour, but test with a cloth to be certain. If the fluid is brown or black, the liquid has been contaminated and the vehicle should be taken to a mechanic.
  • Add fluid if required.

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