A Comprehensive Guide to Car Fluids

myth of frequently changing transmission fluid

Can humans survive without water? Sounds impossible, right? Now imagine a car surviving without fluids.

A car needs a variety of fluids to function properly. There are different types of car fluids in the market and based on which car model you own, it may need some or all of these fluids.

You must have heard the term ‘fluid top-up’ whenever you get servicing for your car. But, not all of us delve deep into what all car fluids there are and just how important they are.

Continue reading to find out which automotive fluids are essential, how they help your car work, and the car fluids to check.

Different types of car fluids to check and how

Keeping a check on your car’s fluid levels saves you money in the long run. The engine in your car is a complicated system. It requires a set of conditions to function optimally and these fluids assist in controlling these conditions. Some fluids help control your vehicle’s temperature, while others lubricate moving parts and control internal temperatures. Here are some of the fluid-dependent systems inside your car and how to check their fluid levels:

Engine oil

All of the moving elements inside the engine are lubricated by the engine oil. Engine oil helps the machine cool down by transferring heat away from the cylinders. Engine oil needs to be changed frequently since it degrades over time and loses its ability to lubricate and protect the engine. 

When to change

Depending on the make and model of your car, the recommended time between engine oil changes is normally between 5,000 and 7,500 miles.

How to check

Take out your oil dipstick and give it a good cleaning with a clean rag or towel. After that, fully re-insert it before removing it once more.

You can now easily find out how much oil is currently in your engine. You’ll notice two markings on your dipstick. The higher mark denotes the maximum oil level, while the lower mark denotes a low oil level that requires refilling. The latter could indicate an engine leak or burning oil, both of which could potentially ruin your engine.

Brake fluid

The performance of your brakes depends on your brake fluid just as much as your engine depends on oil. The fluid performs a crucial function by exerting pressure on your brake pads in opposition to the rotation of the brake disc, causing the car to slow down.

When to change

Your brake fluid needs changing every two years of time given the oil isn’t contaminated in any which way. 

How to check

Many fluids in a car should be inspected including the brake fluid.

You can find the brake fluid canister at the top of the driver’s side of the brake master cylinder. Remove the cap and make sure the brake fluid level is within a half-inch of the cap. Don’t forget to pay attention to the colour. If the colour is black, you better get the fluid changed by a professional.

Transmission fluid

Transmission oil is used in vehicles with automatic or self-shifting transmissions or gearboxes, This oil is often red or green in colour to distinguish it from engine oil and other fluids in the car.

The fluid is tailored for gear lubrication as well as transmission-specific requirements such as valve function, brake band friction, and torque converter performance.

When to change

Checking your transmission fluid frequently is still a good idea. To get an accurate reading, check it when your car is moving and with the engine running.

How to check

Find the fill tube first, then continue (if your car has one). While the car is still running and the gearbox is in neutral (see your owner’s manual), check the level and begin pouring in the transmission fluid. In some car models, you will need help from a professional.


Your engine’s entire output of energy is converted to heat. Without the coolant, the temperature could rise to risky levels and cause major damage. All of this leftover heat is absorbed by coolant, which keeps your engine running at the right temperature.

When to change

As newer automobiles have longer coolant lifetimes, you can replace this important fluid every 2-3 years.

How to check

Look for the radiator cap which is generally marked with the words “cooling system”. Avoid opening it while it’s still hot as a safety measure. And as soon as you do, you can see if the fluid level is full. There are numerous coolants available on the market, and they are available in a wide range of types and hues. Never mix different types of coolant; instead, consult your car’s owner’s manual to determine what it needs.

Power steering fluid

Imagine driving with a stiff steering wheel. It happens when the power steering fluid gets low. 

This fluid aids in maintaining effortless and smooth steering. You can notice a “creaking” in the steering wheel or strange noises as the power steering fluid begins to run low.

When to change

Power steering fluid should be replaced every two years or every 80,000 kilometres.

How to check

You first need to locate the power steering fluid reservoir which is a clear plastic container with a black cap. It will have the ‘MAX’ and ‘MIN’ markings. Now make sure that the fluid is above the ‘MIN’ mark. Fill the container if needed but don’t overfill it. 

Windshield washer fluid

All of us are familiar with this one. Even though we don’t really think of it as a “vital” fluid, it nonetheless has a significant purpose.

When it’s raining or snowing, the windscreen washers will keep your vision clear and keep you moving forward securely. A few times a year, especially after it has rained or snowed and you have been using the washers more frequently, is when we advise checking your windscreen washer fluid.

When to change

The usage of the fluid largely determines how often you need a refill. Generally speaking, you ought to get it filled at each service interval.

How to check

Brightly coloured windscreen washer fluid is the easiest to identify. Typically, the cap is marked with the windscreen wiper symbol. If the washer fluid level is low or empty, top off the reservoir with washer fluid until it is full before capping it back.

Driving your car with low fluids

Driving your car with little or no fluids can be risky for you and other road users. Additionally, it may lead to high repair costs, diminished power and fuel efficiency, and a drop in vehicle value. 

Where low levels of engine oil may lead to engine damage, low coolant levels reduce engine efficiency and increase the risk of overheating the vehicle. Allowing the power steering reservoir to get low can result in difficult or stiff steering, which may result in an accident. 

Low braking fluid gives rise to the problem of irregular brake pressure. It poses a major risk to the driver’s safety as well as the safety of anybody on the road nearby. 

Low trans fluid will result in problematic driving due to harsh shifting, unusual noises, and uncontrolled surging. Last but not the least, a dusty windscreen covered with dirt or mud makes it difficult to see the road ahead. To clear your windscreen, make sure you have windscreen washer fluid.

What happens if you put the wrong fluids in your car

When changing your car’s fluid, be mindful and use only the correct fuel for your car. This is because using the wrong one could cause issues in your car’s performance and functioning. 

Using a fluid that isn’t meant for your car may lead to poor lubrication, overheating of the vehicle and even transmission failure. It’s not always possible to fix the damages caused by using the wrong car fluids. So make sure you’re extra careful when changing these fluids.

However, what’s even worse is putting the wrong fluid into the wrong reservoir, such as putting brake fluid in place of engine oil. This can result in significant mechanical costs that your insurance or warranty is unlikely to cover because it is considered accidental damage if it is not discovered and corrected right after.

You can read the manufacturer’s manual or seek help to avoid this mistake.

Keep your car hydrated

You can’t look after all the maintenance requirements on your own – for example, you will need a professional’s help to change the transmission fluid and engine oil. 

But knowing how you can check all these fluids is essential to keep your car at the top of its game. Make sure to set up calendar reminders to check these fluids from time to time. It might take a bit of time and effort on your part, but trust us, it will save your car for years to come. In case you suspect any issue with your car’s fluids, contact an expert for immediate help.