There are multiple fluids your car and engine use to run efficiently, in some cases, it can be very inconvenient for them to run out, and in other situations, it can be extremely dangerous. 

This guide will explain what each one does, and how to check it if required.

Disclaimer 

In this guide, we’ll explain how to check your fluid levels. If you are in any way unsure of any reservoir locations or types of fluid required, consult your manual or a qualified person. 

Only attempt to fill brake fluid if you are competent in doing so, incorrect fluid usage could cause an accident or serious injury. 

It is important to note, a drastic reduction in brake fluid levels should not be ignored and could indicate a leaking pipe or component. If this is the case, have the car inspected immediately to avoid a repair. 

Brake fluid 

When pressure is applied to the brake pedal, the piston in the master cylinder causes the fluid to move through the pipes and act upon the cylinders in the brake callipers or drums, pushing the brake pads onto the discs and slowing the car. 

The system is sealed to make use of the incompressible property of brake fluid. As air is compressible, if any gets into the lines it can cause reduced braking power. This can happen when the brake fluid runs low in the reservoir.  

Other causes of brake failure include old and degraded fluid and contamination, so it’s important to check the level and change brake fluid when needed. 

How to check your brake fluid 

Locate the brake fluid reservoir, it is usually indicated by a yellow circle or octagon and will have ‘brakes’ on the cap. 

The fluid should be light brown, and not overly dark or light. There should be no contaminants in the reservoir such as leaves or dirt. Wipe the cap clean before opening it to ensure nothing falls in. 

Check the level on the side of the bottle, and fill it with the appropriate fluid to the line specified in the manual. Only use the recommended fluid type as stated in your owner's manual.  

Clutch fluid 

In some manual cars, the clutch is operated by a cable, check your owner’s manual to see if this is the case with yours, if so, you do not need to check your clutch fluid level.  

If your clutch is hydraulically operated, your car will either have a dedicated clutch fluid reservoir, or it may share this with the brake fluid reservoir.  

How to check your clutch fluid 

Look for a similar symbol to the brake reservoir, a circle within an octagon. The cap will say clutch or similar on, if in doubt, consult your owner's manual. 

The level and colour considerations are the same as the brake fluid, it should be a golden colour without blemishes or dark spots. 

Coolant 

Another vital fluid to the engine’s operation, the coolant travels through the engine and radiator, removing heat. Without the adequate flow of coolant, the engine would overheat very quickly, even with moderate usage.  

Depending on the age of your car, the coolant can be in varying colours. With so many different brands using differing colours, it’s best to check the owner's manual to see what type of coolant is best for your car.  

The coolant should be a fairly bright colour. If it is brown or clear then it needs to be refreshed. 

How to check your car’s coolant 

WARNING: Never open the coolant reservoir when the engine is hot. The sudden release of pressure can cause serious burns. 

Locate the coolant reservoir, it is often a black cap with yellow symbols, although Volkswagen vehicles tend to use bright blue caps. Make sure not to confuse the coolant with screen wash in this case. Check the owner’s manual for more information. 

Dilute the coolant to the recommended ratio stated on the bottle, and pour until the level is somewhere between min and max. Do not overfill as too much coolant can cause high pressures to build up in the expansion tank, and leak out. 

Engine oil 

An engine needs adequate lubrication to run, oil coats all the surfaces in the engine and drastically reduces friction and thus reduces heat. If the engine oil is allowed to run out, terminal engine damage will occur.  

Read more about when to change your engine oil in our blog.

Unlike the other fluids, the engine oil is not stored in a reservoir at the top of the engine bay, after the oil has cycled through the engine providing lubrication, it drains back into the sump.  

Engine oil should be checked regularly and inspected for colour and smell. Excessively dark oil can be a symptom of overheating. The oil should not smell of fuel in any way as this can indicate worn piston rings. 

How to check your engine oil level 

The sump or oil pan is a tray-shaped component that bolts to the bottom of the engine. It is where the oil is traditionally drained from and is where the oil level is measured. This is done using the dipstick.  

To check your engine oil locate the dipstick. It is usually fitted with a bright yellow or white handle, it will be either on the front or side of the engine, the latter for rear or some 4-wheel drive cars.

The car's engine must be off and have been for at least 20 minutes, the car should be on a level surface.  

Pull out the dipstick and wipe the oil off with a clean paper towel or cloth, inspect the end to ensure the limit marks are present. The marks will either be notches on the edge or on plastic dipsticks, a patterned section. 

Re-insert the stick, ensuring it is firmly seated back in place. Remove carefully once again and check the level.  

The filler oil cap is usually located on the top of the engine, marked “oil” or with a small oil can symbol. When you remove the oil cap, check for milky residue, this could be a symptom of head gasket failure and should not be ignored.  

It should ideally be in the middle of the two marks, but anywhere inside them is fine. If it's near the bottom or below, add a small amount of oil at a time, re-checking after 20 minutes or so. 

It is important not to overfill the engine oil, as it may cause the excess to be forced out when the engine is running. 

Power steering fluid

Power steering is a luxury taken for granted in modern cars. If your car develops an issue with the PAS (power-assisted steering) system, you will really appreciate how much work it does! 

The power steering will either be hydraulic or electrically operated. Check the recommended fluids section of your manual to work out which one your car is.

If hydraulic, the PAS uses a high-pressure pump and a hydraulic motor to assist in actuating the steering rack, this makes the steering much easier for the driver.

How to check your power steering fluid

Locate the bottle, often they say “Hydraulic Fluid”, “Power Steering” or similar. If in doubt, consult your manual.  

Remove the cap being careful not to allow debris to fall in, and check the colour is bright and not darkening. There are two different types of power steering fluid, usually dependent on vehicle age, your manual will advise which one to use. 

Either use the level on the side of the bottle as before or check using the in-built dipstick depending on the car. Refill till it is in between min and max. 

Screenwash

The screenwash is a special detergent solution, the bottle is usually stored inside the car’s bumper or front bodywork.  

It is likely there will be a filler cap somewhere around the outsides of the engine compartment, with a long translucent tube disappearing into the structure of the car.  

Because the level is usually below this filler tube, the easiest way to check the level is to top it up. Use a high-quality screen wash as cheaper ones can cause streaks and not properly clean the screen. 

All of these fluids are vitally important, and should not only be refilled but replaced regularly. Keep your car running smoothly with interest-free monthly payments on servicing and repairs with Bumper. 

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