The air filter is a crucial part of your vehicle’s maintenance schedule. All ICE vehicles have an air filter before the cold air intake box, ensuring dirt and debris never get into the engine.
Don’t confuse the engine air filter with the cabin air filter. Even though both need occasional replacement, they play different roles and have different replacement cycles.
How Often Do Manufacturers Recommend Air Filter Replacement?
A quick look at your user manual will tell you how often the manufacturer recommends air filter changes. I did a spot check for different manufacturers and came up with the following findings:
- Chevrolet: 45000 miles
- Hyundai: 30000 miles
- Ford: 30000
Every manufacturer halves the recommended miles if you drive in severe conditions. Harsh conditions include:
- Heavy traffic
- Dusty conditions
- Driving on unpaved roads
- Hot weather
How Often Do Experts Recommend Changes in Real Life
While manufacturers might know their vehicles, they have no control over how you use your vehicle. The best way to decide if it is time to change your air filter is to look for signs that it is dirty and clogged.
Regardless of how clean it looks, you should pre-emptively replace it after two years or 15000 miles, whichever comes first.
Signs That It’s Time to Replace Your Air Filter
There are a couple of tell-tale signs you can use to figure out if it’s time to get a new engine air filter. Some of the most reliable include:
A Visual Inspection
A visual inspection is the surest way to determine whether your air filter is clogged and due for replacement or not. Air filters should be white or grey on the screen (some vehicles use different color filters)
Any darkening or changes in color hint at massive accumulations of dust and debris. You can also notice dust particles and bugs in between the filter’s folds.
Since most car owners take their cars in for an oil change every 3,000 to 15,000 miles, it would be convenient to let the mechanic inspect the air filter for you while at it.
If you drive in very extreme conditions, pre-emptively replacing the air filter every 6000 miles (unless it looks very clean and your manufacturer recommends waiting a bit longer) is a good idea.
A Drop in Gas Mileage
Your car’s engine needs good airflow to burn fuel in the combustion chambers efficiently. A clogged filter reduces airflow, making the engine work harder to get the air it needs to run.
While the impact on gas mileage won’t be much, it’s still notable, especially when driving in town.
Note that a drop in fuel consumption could also hint at other problems like faulty sparkplugs, a vacuum leak, a blown head gasket, and so much more.
Ignition Problems and Rough Idling
A failed air filter that lets debris into the engine will lead to a different type of failure. In this case, the gunk will clog up spark plug gaps making it harder to spark correctly.
This problem becomes more evident when cranking a cold car. The engine will crank longer and start sluggish. Sometimes, it won’t start at all. Your engine could get flooded, too, since the injectors will be pumping in fuel that the spark plugs can’t ignite.
Lack of Engine Power
Another sign your air filter is faulty could be a noticeable lack of engine power if this happens when your current air filter is past around 10000 miles or after driving through dusty roads or mud.
Your vehicle will feel sluggish and won’t accelerate as fast as it usually does. If you notice this, you can have the air filter inspected. Remember that other problems in the power train could also lead to engine power loss. Have a mechanic check your car or look into any MIL engine codes to identify and fix any other problems.
A clogged filter will either make your engine run rich, producing less power. The ECU can adjust for the reduced airflow to maintain a good mix, but the overall power output will drop since it will be forced to inject less fuel per cycle.
Black Smoke or a Rich Air Fuel Mixture Warning
Finally, since a clogged filter affects how much air gets to the engine, it could also affect how rich your engine runs.
While the ECU should use the Mass Air Flow sensor to determine how much, there’s still a limit to how low the fuel injectors can dip to match insufficient airflow from a blocked air filter.
If it is too low, your car will either choke and turn off, or it will keep running but in a very rich setting. The result is very black smoke or a rich air-fuel mixture check engine error code.
Can I Wash and Reuse a Car Air Filter
Cleaning and reusing a car air filter is sometimes acceptable – especially if it’s an OEM or a durable performance air filter.
ProTip: Don’t clean standard air filters at all. Just replace them. They are not durable and might become more porous or get tears that will harm your engine more.
Warning: Only clean air filters according to manufacturer recommendation. If you get a warning NOT to clean, then don’t.
How to Clean an Air Filter
- Remove the air filter from the vehicle and inspect it. Look for any holes or tears in the pleats. Holes and tears mean you must replace the filter
- If it is intact, tap the filter on the floor to drop grit off. Ensure you tap with the outside side (the side facing the outside of the intake) facing down since it will have all the debris
- Use a soft brush to rub off any remnants. You can also use a vacuum to suck off any debris and dust from the filter
- Hold the filter to the light after here and see if some light filters through. If it seems opaque, then it is time to replace the filter.
While some guides talk of washing the air filter with water, we don’t recommend it because it introduces the risk of putting water into your engine or pushing it through the MAF if you install the filter before it dries thoroughly.
Air filters replacements could be as cheap as $20. Vacuuming and dusting it is safe and straightforward enough to get slightly more lifespan from the filter. Adding water into the mix seems like more work and trouble for an otherwise easily replaceable unit.
Can I Use Any Air Filter in My Car?
No. Your air filter must be a perfect fit for your car. If it doesn’t fit well, it will have leaks around the seams. This means dust and debris will filter through.
If you can afford it, go for OEM replacement filters specific to your vehicle. They are the best for your engine since the manufacturer will have done extensive research about the filter. If you want to go for an aftermarket, ensure it was designed for your vehicle by confirming fitment with VIN or model, trim and year of the car.