Maintain Your Car By Frequently Replacing These 8 Fluids

What Are The 8 Fluids In A Car That Need Maintenance?

Your vehicle is a well-oiled machine or at least it should be. One of the most important aspects of regular vehicle servicing is the inspection and replacement of important fluids in the vehicle. Every system in the vehicle relies on some sort of fluid for its proper functioning. If you wish to maintain a reliable and long-lasting vehicle then frequent servicing of fluids in the vehicle is the quickest and perhaps the cheapest way. 

Regularly flushing and replenishing the oils and coolant found in various vehicle components is part of preventative maintenance. It eliminates device overheating, seizure, excess wear and tear preserves and prolongs the life of various parts, and improves operating conditions. 

Here are the 8 important fluids found in all modern automobiles:

Engine Oil

The engine oil plays the all-important role of lubricating the numerous engine parts and ensuring that wear and tear within components is reduced. Lubrication oil allows various components to run smoothly and eliminates metal-to-metal abrasion between various components. In the absence of lubricating oil, the engine components moving at extremely high RPMs will undergo rapid wear and the high heat generation will cause the components to seize. Apart from lubrication, the engine oil contains additives like detergents, rust inhibitors, anti-oxidants, anti-foaming agents, etc. that serve specific functions like cleaning the engine, preventing rust formation, oxidation, and foaming of the oil. These additives usually wear out over time and the engine becomes susceptible to issues that the additives are designed to counteract. This makes it important to change the engine oil at regular intervals to maximize engine performance and life. 

To check your engine oil, run the engine for a while, shut it off and then wait for it to cool down. Now examine the oil dipstick that runs into the engine oil pan (usually located at the front of the engine within sight). Remove the dipstick and clean the oil on it, then reinsert it fully and check the level. Marking on the dipstick will indicate oil level and must be above the minimum. Along with the oil level, you must also check the condition. Golden, yellow, or amber indicates healthy and fresh oil whereas darker shades of brown and black mean you must replace the engine oil. If you notice a milky or whitish hue along with the oil, it can mean the coolant is being mixed with the oil due to a gasket or seal failure. The engine oil replacement depends on many factors such as the type of engine oil used, type of vehicle, age of the vehicle and driving conditions. Most manufacturers recommend changing oil every 10,000 km

Engine Coolant

The combustion process produces an immense amount of heat. This intense heat is enough to melt the engine components together and cause complete engine seizure. This is why overheating engines are often allowed to cool down immediately to avert catastrophic results. The engine coolant is a mix of water and antifreeze and dissipates the engine’s heat through the vehicle’s radiator. The coolant follows a continuous cycle in which it passes through the engine block and various cooling system components repeatedly. Over time the coolant becomes very acidic which can harm the engine by causing rusting and pitting and deteriorating the seals and gaskets. Therefore it becomes important to check the coolant condition and flush out the coolant according to the manufacturer's recommended interval or every 100.000 km. Coolant conditions can be hard to determine and even harder to flush completely. We have compiled a comprehensive guide on how to check the condition and flush engine coolant

Brake Fluid

The brakes in modern cars are operated via hydraulic pressure. The most essential part of any hydraulic system is fluid. In the case of the braking systems, special brake fluid is utilized that transfers the force applied at the brake pedals to each brake caliper or drum and actuates the brakes. If the brake fluid is low in the system, it can compromise the brakes completely. The application of brakes occurs instantly and if you feel the brake pedal is spongy or has a lot of travel, start by checking the brake fluid level.  

The brake reservoir stores the brake fluid and is found above the brake master cylinder. Open the reservoir cap, being careful not to drop any dirt into the reservoir. Inspect the level of the fluid making sure it is within indicated levels. If the brake fluid is low then add the compatible brake fluid - info on which can be found in your owner’s manual. Low brake fluid can also be due to worn-out brake pads or a leakage in the brake lines. The color of the fluid indicates its condition. Completely flush and bleed the brake system If the brake fluid is dark, cloudy, or opaque as it indicates contaminated and/or old fluid.

The brake fluid is hygroscopic in nature. What that means is it absorbs moisture from the air which can cause brake line rusting. Therefore, It is recommended to replace the brake fluid every 2 years or 50,000 km.

Power Steering Fluid

Modern cars are crowded with features that make driving a relaxing and comfortable experience. One of the most convenient innovations is power steering. Much like the brake system, the power steering system also relies on hydraulic pressure for operation (non-electric power steering systems). If you notice that the steering effort has increased then check the power steering fluid level and refill with recommended fluid type. Most manufacturers do not have specified service intervals for power steering fluid but it is advised to replace the fluid every 100.000 km. A very dark or black fluid colour means it's time to replace your power steering fluid. Have your local mechanic inspect the fluid condition and flush the system.

Transmission, Differential & Transfer Case Fluids

The transmission or gearbox houses many different rotating gears and shafts, most of which are in constant rotation with the engine. These gears need to be kept well lubricated for optimal performance and swift gear shifts as well as preserving the life of the components. Some cars have a dipstick for the gearbox similar to one found on the engine for checking the engine oil. With the engine running, check the transmission fluid level and condition. Very dark or black colour and a burnt odour can indicate contaminated fluid. If your vehicle lacks the transmission dipstick, have your mechanic inspect the transmission fluid. Most manufacturers recommend replacing transmission fluid within the 50,000 to 100,000 km range. If you have an automatic transmission with more than 250.000 km and you have never carried out a transmission fluid change before then changing the fluid now can cause many problems. In such cases, it is advised not to carry out fluid as that can cause transmission slipping or seizure. To learn more about this refer to this article on common car myths

The differential and transfer box also contain an array of gears, shafts and other components that require constant lubrication for their smooth operation and heat dissipation. Most vehicles use transmission fluid for these devices. As the differential and transfer boxes are fully sealed, they require less maintenance. But it is advised to carry out fluid replacement every 100,000 km.

Clutch Fluid

Some vehicles have a hydraulic clutch actuation mechanism similar to the brake system and use clutch fluid for force transfer through hydraulic pressure. In most vehicles, the brake fluid is used as the clutch fluid as well. Since the clutch operation relies on the fluid level, low clutch fluid can directly translate to hard shifts, vibrations when changing gears, and spongy or abnormal clutch pedal behavior.

The clutch reservoir sits above the clutch master cylinder. Refer to your owner’s manual for its location and replacement interval. It is a good idea to service your clutch fluid along with the brake fluid every 2 years or 50,000 km.

Air Conditioning Refrigerant

The AC system found in the vehicle is able to produce favorable temperatures and moderate the cabin air with the help of a refrigerant or freon agent found within the system. The vehicle's AC compressor pumps this refrigerant throughout the system. The refrigerant is mixed with the necessary lubrication oil for the AC compressor. Always make sure to add the right compressor fluid type along with every refrigerant replacement. If you notice the cabin air coming through the vents is not cold, then have the AC system inspected by a professional. One of the major failure points for the AC system is the AC compressor. You can read more about how to diagnose the AC system in your car.

Windshield Washer Fluid

Last but not least - the windshield washer fluid is responsible for providing the driver with a clear view of the road during the worst weather or road conditions. It is easy to neglect the washer fluid but when it comes in use, it makes the difference between a safe drive and an inadvertent pitstop. Filling the washer fluid is simple, just locate the cap that says washer or windshield and top it up with suitable washer fluid of choice. In winter you may have to add some antifreeze or alcohol to prevent freezing. 

Having proper amounts and fresh fluids and oils within all the working mechanical and other systems in your vehicle will ensure your vehicles last longer, the components run freely with minimal undesirable restrictions and maintain various systems in peak operating conditions. Fixing up the various fluids at their recommended service interval is a great practice that every car owner must follow. 

Make it a habit to frequently check all the mentioned fluids. Because any irregularities with the fluid can even indicate budding issues within the whole system itself - saving you in repairs before things get worse.  


Q) Is It Necessary To Replace Engine Oil Filter Along With Oil Replacement?

Wear and tear in the engine causes small metal bits to chip away and this contaminates the oil over time. The oil filter ensures this crud is contained, but eventually the oil filter fails (more than 15,000 km) and the crud can move freely. These contaminants can flow through the tiny engine offices and restrict oil movement, causing serious engine damage and seizure or acting as abrasives, increasing wear on other components. This is why it is always recommended to replace the oil filter with every oil change. 

Q) What Colour Are Various Vehicle Fluids?

Most fluids in the vehicles are purposely dyed a specific colour for easy leak detection. Here are the commonly found colours for various passenger car components: 

Engine Oil: Light Brown, Golden, Yellow or Amber

Brake Fluid: Transparent Yellow to Light Brown

Transmission Fluid: Red or Brown

Power Steering Fluid: Clear, Red or Brown

Coolant: Green, Orange, Pink, Red or Blue-Green

Q) What Type Of Oil Should I Use In Various Parts?

Every component like the engine, transmission, power steering, etc requires a special blend of fluid. These components are generally designed according to the specific fluid type and so using a different fluid type can cause considerable damage to the components. Always refer to your owner’s manual for information on the right type of fluids for each system.


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John Framigllia
Technical Writer
Our technical writer is known for simplifying automotive parts and services. Intuitive with various vehicles and manufacturers, he knows how to simplify complicated problems.