Fluids and Filters: When Do They Need to Be Changed?

A vehicle getting an oil change in Las Vegas, NV

Winchester, Virginia – LOF. There was a time when any car owner would recognize what those letters stood for. Every three months or three thousand miles, folks would head to the service station (or to the garage) for a Lube, Oil, and Filter. A technician (or you or your dad) would replace the engine oil and filter, and would lubricate several suspension components with grease. It didn’t seem to matter what kind of car you drove; everyone was under the same set of “rules”. Three months or three thousand miles, time for a LOF.

Times have changed

But things are different today. Of course, you still need to get your car’s oil and oil filter replaced regularly. It is no less important than it was years ago. But the length of time between oil changes has increased. Oh, sure, you might find the occasional quick oil shop that still insists your car needs fresh oil every 3k miles. Most manufacturers, however, recommend an oil and filter change closer to 5k miles – and sometimes longer. If you opt for synthetic motor oil, you may be able to substantially increase the miles between oil changes.

The length of time between oil changes is not all that has changed. Cars of the past required regular lubrication of the suspension system. Suspension components included grease fittings so that a technician could add fresh grease. This was often done at the same time as an oil change. But today’s cars, trucks, and SUVs usually have sealed components that do not require a “lube.” The grease inside these modern parts is designed to last the lifetime of the part. So, not only does your car not need oil every three thousand miles (in most cases), but it does not (in most cases) need to be lubed either.

What it does need from you is regular maintenance. Naturally, that includes replacing the oil and the oil filter. But your car contains other fluids that need to be checked and changed too. And there are other filters that need replacement. Here is a list of the fluids and filters that need your attention and should be checked from time to time, and some general guidelines suggested by manufacturers. (Note: These guidelines are general. Consult your owner’s manual or check with a trusted repair shop for specific recommendations for your vehicle.)

Fluids and Filters

Engine Oil provides lubrication for the moving parts inside the motor. Without it, the pistons, rods, camshaft(s), valves, and more would wear out pretty fast. Most manufacturers recommend replacement between 5k-7.5k miles. Synthetic oil (such as Mobil 1™) can increase this interval.

Engine Coolant circulates through the engine block to pick up excess heat that develops during the combustion process. Without the coolant, the engine would quickly overheat and could receive significant and costly engine damage. Also known as “antifreeze” for its ability to withstand cold temperatures, the engine coolant should be replaced anywhere between 45k and 150k miles, depending on the vehicle manufacturer. The type of coolant to be used varies from one manufacturer to another as well.

Automatic Transmission Fluid (ATF) is hydraulic oil used inside automatic transmissions. If your vehicle has a manual (stick) shift transmission, it does not have ATF. The fluid gets contaminated over time and needs to be replaced as frequently as 45k miles or up to 90k miles, although some manufacturers recommend that the fluid in their transmissions should last the lifetime of their vehicles. Because simply changing the ATF does not replace all of the fluid (nearly half of the ATF is housed inside the torque converter and will not drain out) some repair shops suggest that you consider a transmission fluid flush where ATF is forced through the transmission and all of the fluid is replaced.

Brake Fluid is hydraulic oil that allows pressure to be transferred from your brake pedal to the brake calipers when you want to slow or stop your car. Brake fluid is neglected by many vehicle owners (your brake fluid warning light may be an indicator) but should be replaced every 45k miles or so because water gets into the system and causes the brake fluid to degrade.

Power Steering Fluid is not usually recommended by manufacturers for regular replacement. Some dealerships and repair shops recommend replacing the fluid, but their recommendations vary. This fluid allows the power steering system to make turning the steering wheel easier. A loss of fluid would affect normal steering operation, so its level should be monitored.

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, 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).

The Oil Filter has already been noted as a component that needs to be replaced whenever the oil is changed. The oil filter traps dirt and debris (metal particles inside the engine resulting from engine wear) and removes it from the oil.

The Engine Air Filter cleans the air that your engine uses to breathe. In order for combustion to happen, a mixture of fuel and oxygen needs to enter the combustion chamber. This filter traps dirt and debris before it enters the intake manifold so it does not get inside the engine. In order to keep the engine air filter from getting clogged, it should be replaced every 15-30k miles, more frequently if you drive in dirty conditions.

The Cabin Air Filter cleans the air that you breathe inside the passenger compartment. Air coming into the vents is filtered to maintain a clean environment inside your car. Replace the cabin air filter every 20-30k miles to ensure the heater and air conditioner do not have to work overtime to pass air through the filter and the system, and to prevent foul odors from developing.

The Transmission Oil Filter strains out small, hard debris that could cause premature wear inside the transmission. Along with ATF replacement (or a transmission fluid flush), this filter should be replaced according to manufacturer’s recommendations.

The Fuel Filter makes sure that any sediment inside the fuel you put in your car does not enter the fuel system. Dirt can plug injectors and negatively affect engine performance. The fuel pump also has to work harder if the filter is plugged. Have the fuel filter changed every 30-60k miles.

Yes, times have changed. You might not have to lube your car’s suspension anymore, but it’s a lot harder to check the transmission fluid. And who even knew there was a cabin air filter to contend with? With all of the fluids and filters that need attention, make sure to make an appointment to have your car cared for by the professionals at Hogan & Sons Tire and Auto.

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 Hogan & Sons Tire and Auto 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, Hogan & Sons Tire and Auto 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.

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