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The factory-recommended replacement intervals for filters can vary quite a bit depending on the year, make and model of the vehicle, as well as how it is driven. As a rule, older vehicles (those more than 15 to 20 years old) typically have more frequent service intervals than newer vehicles. Why? Because late-model vehicles require less maintenance, thanks to improvements in motor oils, transmission fluids, engine design and filter media.
Many long-life air and oil filters use synthetic fiber media or a blend of cellulose and synthetic fibers to extend filter life.
Changing the oil and filter every 3,000 miles was standard practice decades ago. But it’s no longer necessary because most multi-viscosity oils today are a synthetic blend or a full synthetic that resist viscosity breakdown and oxidation for a much longer period of time. Late-model fuel-injected engines also run much cleaner than their carbureted ancestors, which reduces oil contamination in the crankcase.
Oil and filter change intervals for most late-model vehicles range from 5,000 to 7,500 to 10,000 miles or more. Many vehicles don’t even have a time/mileage recommendation anymore but rely on a computer algorithm to turn on a “service reminder light” when an oil change is needed.
A key point with today’s extended service intervals is that they depend on two things: using a top-quality motor oil that meets OEM service requirements, and a premium or long-life oil filter (brand name or private label) that has the storage capacity to go the distance without clogging.
The most common mistake that’s made when recommending or choosing an oil filter is to go with the least expensive filter on the shelf. That can be a big mistake if a customer is not changing their oil for 5,000 miles or more. Many economy filters lack the storage capacity to go beyond 4,000 or 5,000 miles before they clog and go into bypass mode and route unfiltered oil to the engine.
Our advice is to always recommend a premium or extended-life filter to every customer who is following extended service intervals, as well as customers who are buying synthetic motor oil because they want the best protection for their engine.
Recommended replacement intervals for engine air filters can range from 30,000 to 50,000 miles or more, but it depends more on exposure to dirt than time or mileage. The dirtier the environment, the more often the air filter should be replaced. Inspecting the air filter when the oil is changed is the best way to tell if it is dirty.
Cabin air filters that trap both dust and odors typically have a service life of about one year regardless of mileage because the charcoal particles that absorb odors degrade over time. Dust-only cabin air filters should be inspected and/or replaced every two years or 30,000 miles, or as needed depending on operating conditions.
In-line fuel filters typically have a recommended replacement interval of 30,000 to 50,000 miles. But many of today’s fuel filters are part of the fuel pump module assembly inside the fuel tank and are “lifetime” filters with no recommended replacement interval. The filter should have enough capacity to last upward of 10 years or 150,000 miles – unless the fuel is somehow contaminated with a tank of dirty gas (it happens!).
Most late-model automatic transmission filters also are “lifetime” filters with no specified replacement interval. Under “normal” use, the fluid and filter often can go upwards of 10 years or 150,000 miles. However, many transmission experts still recommend changing the fluid and filter every 50,000 miles for preventive maintenance. Fluid and filter life can be cut short if the transmission runs hot (towing can cause this), or as a result of hard use. Discolored fluid that smells like burned toast is a sign of overheating and should be changed without delay.
Air filters, cabin air filters, oil filters and (sometimes) fuel and transmission filters are important maintenance parts that typically are replaced according to a time and/or mileage schedule. A vehicle’s service schedule recommendations can be found in the owner’s manual or in a separate brochure. Unfortunately, many motorists never read – or totally ignore – the recommendations.
Factory service schedules are designed to prolong the life of the engine, transmission and cooling system, to reduce premature wear and breakdowns, but also to minimize maintenance costs while the vehicle is still under warranty. That’s why factory oil change recommendations have been stretched to 7,500 to 10,000 miles or more on many late-model vehicles. Most late-model cars and light trucks no longer have recommended change intervals for transmission fluid and filters, or for fuel filters. These so-called “lifetime” fluids and filters are supposed to last a long time – but they won’t last forever. Experience has shown that “lifetime” filters and fluids don’t live up to the hype.
Fuel filters always should be replaced when a fuel pump is replaced (unless the filter is part of the fuel pump module assembly). Likewise, transmission filters should be replaced if a customer is changing the fluid in their transmission.
Last Line of Defense Against Contaminants
Filters are the first line of defense against contaminants. Air filters keep dirt and abrasive particles out of the engine. A good-quality air filter will trap about 98 percent or more of the particles that can cause trouble inside an engine. As the filter media becomes saturated with dirt, it’s efficiency actually increases. But, as the filter becomes clogged with more and more dirt, it also becomes more restrictive to airflow. The greater the pressure drop across the filter, the more it hurts performance and fuel economy.
Ideally, an air filter will be replaced before it causes a restriction in airflow. Whether or not an air filter goes 30,000 miles or 50,000 miles before it needs to be replaced depends on driving conditions and how much dirt the filter has ingested over those miles. Driving on dusty rural gravel roads is a lot different than suburban or city driving. Air filters need to be inspected regularly and changed more on an “as needed” basis than the mileage on the odometer.
The same advice goes for cabin air filters, which typically need to be replaced every couple of years. Carbon-impregnated “odor” filters are only good for about a year before they lose their ability to absorb odors. Cabin air filters are an often overlooked maintenance item because many motorists are unaware their vehicle has one, or how often it should be changed. The filters usually are located behind the glovebox or under a panel in the cowl area of the windshield.
With oil filters, the situation is a little different. An oil filter traps dirt and metallic wear particles in the crankcase to protect the bearings, rings, camshaft and valvetrain components. The life of the oil filter depends on how rapidly contaminants are generated inside the engine. If the air filter is doing its job and prevents dirt from being sucked into the engine, and the rings and cylinders are in good condition and holding a tight combustion seal, and the oil is doing its job of minimizing wear, an oil filter easily should last until the next oil change is needed.
Oil filters have a built-in bypass valve so if they do become clogged and the pressure differential becomes too great, the bypass valve will open, allowing the engine to maintain normal oil pressure. The only problem is that the oil will be unfiltered, which means the bearings, cam and valvetrain have no protection against abrasive wear particles. The small size and limited dirt-holding capacity of many late-model oil filters means regular changes are a must.
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