Car fluids: An owner's guide
Cars can be, in many ways, like people. We sometimes give our cars names (and even nicknames). In addition, they have vital parts that keep them running and bodies that need maintenance and repairs. Another similarity? Just as people have fluids like sweat, blood and saliva to help regulate their body, cars also have essential car fluids that are vital to helping them operate.
As a car owner, learning about car fluids may prove helpful since most car maintenance routines recommend checking your fluids periodically. Let’s learn more about six major car fluids in your vehicle.
Engine oil
Engines have moving parts that can potentially rotate several thousand times a minute. Engine oil is an essential car fluid used to provide lubrication to prevent these parts from generating excessive friction that would wear them out faster. Engine oil also assists in cooling the engine.
Where to find it
Engine oil dipsticks are usually located within or close to the engine bay itself. Your owner’s manual should have specific information on how to find it, or you can ask your mechanic.
How to check it
When trying to check engine oil, your mechanic will likely ask you to wait at least 10 minutes after shutting off the car to let the engine (and the oil) cool down, and so the oil can settle. Next, they’ll likely remove the dipstick and wipe it clean before re-inserting it and pulling it back out again. The dipstick generally has two markings, indicating the maximum and the minimum levels of oil your engine should have. It’s generally preferable to keep your oil closer to the maximum level.
Your mechanic may also check the oil on the dipstick with their fingers to ensure it still has a smooth consistency and a honey- or amber-like color. If it’s discolored or has a gritty feel, it’s most likely time to replace it.
When to replace it
In general, engine oil is meant to be replaced roughly every few months to a year, depending on the motor and type of oil you’re using. Your owner’s manual will likely have a recommendation for how often engine oil should be changed.
Your regular driving conditions may also influence how frequently you need to change your engine oil. For instance, drivers who tow heavy loads, live in dusty environments or engage in frequent stop-and-go driving may need to change their oil more often.
How to identify a leak
As mentioned earlier, engine oil typically has a color like honey or amber. If you notice a stain of this color where your car was recently parked, it may indicate an engine oil leak. A low reading on the engine oil dipstick may also suggest an oil leak.
Coolant
Engines produce heat. Coolant is the car fluid that works to absorb that heat and carry it away from the engine block, typically dissipating it via the radiator. This function regulates engine temperature and prevents damage from overheating. Coolant is also called antifreeze because it contains additives that prevent freezing in the winter. This helps prevent cold-weather damage to the engine, radiator and water pump.
Where to find it
Coolant is typically in the radiator, though some vehicles may also have coolant flowing to other systems. There is generally also an overflow or expansion tank that connects to the radiator and gives the coolant additional space to expand as it absorbs heat.
How to check it
As with your engine oil, when checking your coolant your mechanic will likely ask to wait for the automobile to cool after shutting off the engine. The mechanic would then most likely look to see that the coolant is somewhere between the minimum and maximum levels indicated on the side of the tank. If the level is low, they may recommend topping it off. Most mechanics will also unscrew the radiator cap to check coolant levels. If not at or near the top of the radiator, they may recommend topping off the coolant.
When to flush it
Coolant is generally meant to last for several years and tens of thousands of miles at a stretch. However, it’s best to consult your owner’s manual for manufacturer’s recommendations on when to flush the coolant in your specific car.
How to identify a leak
Consistently low levels of coolant could indicate you have a leak, as could stains or residue matching the color of the coolant you use for your car (coolants can come in many different colors).
Additionally, if your engine oil looks cloudy the next time you check it out, it may indicate your coolant is leaking into it.
Power steering fluid
If you’ve ever driven a classic or vintage car, you may have noticed how heavy the steering feels compared to newer cars. That’s because newer cars have hydraulic power steering systems that use pressurized fluid to help make steering and maneuvering less effort.
Where to find it
Power steering fluid typically has its own dipstick or cap somewhere on the engine bay, generally labeled as power steering.
How to check it
Checking power steering fluid is very similar to checking engine oil or coolant (above), in that it requires removing and checking the dipstick or the markings on the reservoir and topping it off with the manufacturer’s recommended fluid if the levels are low.
When to flush it
Power steering fluid is typically designed to last quite a while, but manufacturers may recommend flushing it after a certain number of miles. It’s best to consult your owner’s manual to see what your manufacturer says.
How to identify a leak
One sure sign of a power steering fluid leak is if you find yourself constantly having to top it off. A leak in the power steering may also cause the steering to feel sluggish and heavy. Power steering fluid is often pinkish in color, so stains or residue in this color may also indicate a potential leak.
Transmission fluid
Transmission fluid serves a similar function as engine oil by cooling and lubricating parts throughout the drivetrain. This is a big job because the transmission needs to provide smooth, seamless shifting. Problems with transmission fluid may make for a thoroughly unpleasant drive, so it helps to know what to look for.
Where to find it
Your car may or may not have a dipstick to check the transmission fluid. If it doesn’t, you may have a sealed transmission.
How to check it
If your car has a dipstick for the transmission fluid then the procedure is almost identical to checking other car fluids. If it doesn’t, your mechanic will have to perform a more involved procedure to check it. Transmission fluid is often a reddish amber color, but this may vary.
When to flush it
Some cars have “lifetime” transmission fluid that requires minimal maintenance and should hopefully never need replacement. Nonetheless, as with many of the other car fluids on this list, if the appearance of your transmission fluid becomes discolored or dirty looking, there’s likely something wrong with it.
As always, it’s best to consult your owner’s manual and follow the manufacturer’s recommendations on how to service your transmission.
How to identify a leak
Reddish-brown stains or puddles on the ground near where you parked may indicate a transmission leak, as could consistently low fluid levels. Moisture around the transmission may also indicate a leak.
Brake fluid
Brake fluid helps to transfer the force from the brake pedal to the actual brake calipers themselves. These calipers (along with the brake pads) then clamp down on the wheel to create the friction required to slow down or stop your car.
Where to find it
Brake fluid is typically stored in a reservoir in the engine bay, generally marked off in some way to indicate what it is.
How to check it
Checking the brake fluid is usually a simple procedure that requires taking off the reservoir cap and visually inspecting to make sure the fluid inside is near the top.
When to flush it
Brake fluid has a generally transparent amber coloration. Any discoloration could indicate an issue that requires flushing. Beyond that, brake fluid tends to get flushed every couple of years or so. It’s best to change it based on the manufacturer’s recommendations in your owner’s manual.
How to identify a leak
Brake fluid leaks can cause the brakes to feel irregular, “spongy” or soft. Additionally, visible fluids under the car, consistently low fluid levels or the presence of a brake warning light on your dashboard may also be potential signs of a leak.
Windshield washer fluid
Windshield washer fluid doesn’t make a tangible difference to the performance of your car, but it affects visibility through your windshield, which shouldn’t be taken lightly.
Where to find it
The windshield washer fluid is often stored in a translucent tank somewhere under the hood. This feature allows it to be easily identifiable since most washer fluids come in bright colors. The windshield fluid tank will usually be labeled as well.
How to check it
A visual inspection of the washer fluid tank should typically suffice. Since it’s not essential to the mechanical functioning of your car, another potential (but less pleasant) way to discover you’ve run out is to try to use it and have nothing come out of the nozzle.
When to flush it
Flushing out the windshield wiper system isn’t typically a routine procedure. If, however, you notice uneven, inconsistent spraying (or no spraying at all) even when you have adequate fluid, it could mean there’s a blockage that requires a mechanic’s attention.
How to identify a leak
Consistently low fluid levels are often the most obvious indicator of a windshield washer fluid leak. Other signs may include puddles or wet stains near the vehicle.
In summary
Car fluids come in many varieties beyond just the big six listed here, and each serves a specific and important purpose. As a car owner, understanding how and when to check and service these car fluids, as well as diagnose potential leaks, could help extend the quality and life of your ride.
