“Three years or thirty thousand miles!” Ever hear that mantra? It is probably safe to assume that most car owners know that the engine oil needs to be replaced at regular intervals. But would It surprise you to find that many do not understand when it should be changed? And what about all of the other fluids that are integral to the function of a car? Do any of those need to be replaced? If so, which ones and how often?
Several of the mechanical systems on a car, truck, or SUV require some form of fluid for operation. The type of fluid depends on the purpose of the system. For instance, the engine needs lubrication, so engine oil (also known as motor oil) coats the moving parts to prevent friction and wear. The engine also needs to operate within a specific temperature range, so engine coolant (antifreeze) is circulated throughout the engine block to regulate the temperature. Both of these systems, engine lubrication and engine cooling, serve different purposes, and each requires a different fluid.
Some systems and their respective fluids are common to any vehicle. All vehicles have an engine that needs oil for lubrication and coolant for temperature control. All have brakes that use hydraulic oil, or brake fluid. Today, most have automatic transmissions that rely on transmission fluid, and power steering with its own oil.
But some types of fluids are only used on certain vehicles, such as those with four-wheel- or rear-wheel-drive. In any case, each fluid is formulated for a specific purpose – lubrication, cooling, hydraulic pressure. Each fluid is different. And it is important to know when to have each fluid replaced.
Vehicle manufacturers will have a recommended service schedule for fluid replacement. Some fluids are changed frequently; some (according to the manufacturer) are not changed at all . Here is a list of different types of fluid used in a vehicle and some examples of when they might need to be serviced. (Note: These examples are for discussion purposes only. Check your vehicle owner’s manual for specific information about your car.
Engine Oil coats the internal moving parts of the engine to provide lubrication. Without this lubrication, the pistons, rods, crankshaft, camshaft(s), valves, and other components would quickly wear out. The old standard recommendation was to replace the engine oil and filter every three thousand miles; many quick oil change stores still perpetuate this idea. The truth is, most vehicle manufacturers recommend that the oil be changed anywhere from 5,000 – 7,500 miles, not 3k. (The recommendation for both the Chevrolet Malibu and the Honda Accord is 7,500 miles). If synthetic motor oil is used, the interval may be significantly longer.
Engine Coolant is circulated through the engine block by the water pump to absorb excess heat caused during the combustion process and prevent overheating. The coolant exits the engine through a hose and is “cooled” in the radiator before returning to the engine for another round. Engine coolant (also known as antifreeze for its ability to resist freezing) is a mixture of water and (usually) ethylene glycol. Different vehicle manufacturers require different types of coolant – not all are of the same composition. Make sure the coolant added to your vehicle is the correct type. Replacement intervals may range from 45k miles to 150k miles.
Automatic Transmission Fluid
Automatic Transmission Fluid (ATF) is the hydraulic oil used in automatic transmissions. If your vehicle has a manual (stick) shift transmission, it does not have ATF. Over time, the transmission fluid can get dirty and have a burnt smell that develops from overheating, especially with heavy use such as pulling a trailer. On some vehicles, the transmission fluid can be checked and filled from the engine compartment, like the engine oil. But many newer vehicles have “sealed” transmissions that can only be serviced by an experienced technician. There is no dipstick to check the fluid level and no place to add fluid (except under the vehicle). Maintenance intervals can be as close together as 45k miles or as far apart as 90k miles. Some manufacturers even recommend that the original transmission fluid should last the lifetime of the vehicle.
Brake Fluid is not commonly thought of as a maintenance item. It is the hydraulic oil that transfers pressure to the brake calipers when you step on the brake pedal. Many vehicle owners are not aware that the manufacturer recommends replacing the brake fluid. But, over time, the fluid can break down and lose some effectiveness. Manufacturers recommend replacement every 45k miles or so.
Power Steering Fluid
Power Steering Fluid is another of those out-of-sight, out-of-mind fluids that owners tend to neglect. The steering in modern vehicles is enhanced by a hydraulic pump that makes steering easy. Most manufacturers do not have a scheduled replacement interval for this fluid. Some dealerships and service shops recommend replacing the fluid, but intervals can vary widely. At least, the fluid level should be checked periodically.
Differential Fluid is most often related to rear-wheel-, four-wheel-, and all-wheel-drive vehicles that have front and/or read differentials that use a special fluid for lubrication. Replacement intervals can range from 150k miles for light-duty use to 30k miles for a large work truck or one that regularly pulls a heavy load.
Transfer Case Fluid
Transfer Case Fluid, like differential fluid, is also a component on multiple-powered axle applications. The transfer case is a gearbox that transfers power to front or rear axles and it has its own fluid. Some manufacturers do not include a maintenance schedule, whereas others do provide a recommendation. (Ford recommends changing the transfer case fluid in an F150 at 150k miles for normal driving or at 60k miles when towing a trailer or in harsh conditions).
Vehicle system applications have become far more specific than those found in cars of the past. So has the use of fluids in those systems. Manufacturer recommendations have followed suit. Gone are the days when general rules-of-thumb could be applied across all makes and models. And the fluids used in today’s vehicles are often more high-tech and capable of longer lifespans.
When it comes to maintenance of your vehicle, check your owner’s manual for the manufacturer’s recommendation or have a conversation with a trusted and professional technician about the best fluids to use and the best time to use them.
Columbia Auto Care & Car Wash | Author: Mike Ales | Copyright
This article is intended only as a general guidance document and relying on its material is at your sole risk. By using this general guidance document, you agree to defend, indemnify and hold harmless Columbia Auto Care & Car Wash and its affiliates from and against any and all claims, damages, costs and expenses, including attorneys’ fees, arising from or related to your use of this guidance document. To the extent fully permissible under applicable law, Columbia Auto Care & Car Wash makes no representations or warranties of any kind, express or implied, as to the information, content, or materials included in this document. This reservation of rights is intended to be only as broad and inclusive as is permitted by the laws of your State of residence.