Important Auto Fluids To Check

May 7th, 2023 by

When it comes to keeping a vehicle running safely, smoothly, and efficiently, fluids play a major role. Checking six common fluids regularly to make sure they are at the proper level goes a long way toward ensuring your vehicle operates at its highest level and lasts for years to come. At John Sinclair Nissan in Cape Girardeau, Missouri, we want the best for our customers and their vehicles. Our service department is here to help and can answer any questions you have about checking and changing your fluids.

Engine Oil

Engine oil is a vehicle’s most important fluid (apart from fuel) because it keeps an engine running smoothly. In fact, without oil, an engine will only run for about 15 minutes, and this will cause serious damage. Oil’s lubrication properties protect the engine’s parts and prevent damage by reducing friction as the engine rotates thousands of times a minute and its pistons speed up and down. In addition to being a lubricant, oil keeps an engine cool by absorbing friction heat, prevents corrosion of the engine surface, and dissolves particle deposits and impurities.

To check a vehicle’s engine oil, start by turning the engine off. Then, remove the dipstick and wipe it clean. Reinsert the dipstick and pull it out to view the amount of oil in the engine against the maximum and minimum markings. The level should read close to the maximum. If it’s closer to the minimum, add oil following the owner’s manual recommendations.

It’s also important to consider the condition of the oil. The oil should be yellow to amber in color and drip effortlessly from the dipstick. You should get an oil change if it is dark brown to black and clings to the dipstick.


Another essential fluid to the function of a vehicle and its engine is coolant. Coolant prevents engines from overheating. The moving parts that give an engine its power also produce plenty of heat, and coolant absorbs the heat as it flows through the engine and carries it to the radiator, where fresh air cools it.

The method to check a vehicle’s coolant level varies depending on whether or not the vehicle has a coolant reservoir. In either case, allowing an engine to cool down is crucial before checking the coolant.

To check the coolant level on a vehicle with a reservoir, look for the plastic tank and ensure the coolant is between the minimum and maximum fill indicators. For vehicles without coolant reservoirs, unscrew the radiator cap to view the coolant level. It should be visibly filled to the top. If needed, top it off with a coolant approved for your vehicle.

Transmission Fluid

Transmission fluid’s purpose is similar to engine oil in that it lubricates moving parts. A transmission comprises gears, shafts, clutches, valves, and numerous other parts that work together to shift power from the engine to the wheels. Transmission fluid reduces friction and cools the transmission to ensure smooth shifting.

Newer vehicles don’t have access points to check the transmission fluid, but you can stop by our service department and have our professionals check it for you. Older vehicles have dipsticks that allow you to check the fluid in the same way as the engine oil but with the engine running. If you’re able to check it yourself and need to add more, always use transmission fluid approved by the vehicle manufacturer.

In addition to checking that the transmission fluid is filled to the proper level, you should inspect its condition. Transmission fluid should be amber to red and feel smooth to the touch. If the fluid is gritty and dark in color, it’s best to have a mechanic inspect the transmission.

Brake Fluid

Brake fluid is a major component of a vehicle’s stopping power. Braking systems rely on the hydraulic pressure of brake fluid to connect the brake pedal to the wheel’s brakes. Stepping on the brake pedal causes the fluid to pressurize, which tells the brakes to slow the vehicle.

When a brake pedal starts to feel spongy, it’s a good time to check the brake fluid. Remove the brake fluid cap and look into the reservoir. The fluid should be translucent in color and filled nearly to the top. If the brake fluid is low, make sure to add a type that’s compatible with the vehicle, and if the color or consistency seems off, it should be replaced.

Power Steering Fluid

Like braking systems, traditional power steering systems are hydraulic. The pressurization of power steering fluid makes turning the steering wheel smooth and easy. If it starts to feel hard to turn a vehicle’s steering wheel, the power steering fluid might be low, which means it’s time to check it. Depending on the vehicle, there will either be a dipstick with minimum and maximum fill markings or a power steering fluid reservoir with fill markings.

To top off the fluid, use the type recommended by the vehicle manufacturer. If the fluid seems to be getting low frequently, there may be a leak, so you should bring in your vehicle to have the power steering system inspected.

Windshield Washer Fluid

While running low on windshield washer fluid doesn’t affect a vehicle’s performance, it can affect your ability to drive safely when the windshield is dirty and you can’t see the road ahead clearly. Windshield washer fluid reservoirs don’t have a cap with a dipstick or markings on the container, but it’s easy enough to know when the fluid is getting low. Most modern vehicles have sensors that turn on a dashboard warning light when the fluid is near empty. For vehicles without sensors, when the washer fluid starts spraying less powerfully and sporadically, it’s time to add more.

Add windshield washer fluid to a vehicle by slowly pouring it into the reservoir until the fluid reaches the top of the reservoir’s neck. Different types of windshield washer fluid are available. Some have additives to remove bugs, some promote the beading of rain for a clearer view, and some are rated for outdoor temperatures that drop below freezing.

Visit Our Service Center in Cape Girardeau, MO

Come visit us at John Sinclair Nissan in Cape Girardeau, MO. Our factory-trained service technicians perform oil changes and multi-point inspections to ensure all of your vehicle’s fluids are at the proper level, which can prevent costly repair bills in the future and provide peace of mind.


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