Referring to your owner's manual is the best way to determine when your air filter needs to be replaced. Generally, this is every 12,000 to 15,000 miles, but this can vary depending on your vehicle. As a rule of thumb, it's important to keep track of how long the air filter has been in place. The recommended average length of service is 10,000 to 15,000 miles, which for most people is approximately once a year.
However, this is just a recommendation and doesn't take into account your individual driving situation. If you can't tell by looking, but it's been more than three years or 30,000 miles, you should probably buy a new one (especially if you can save money doing it yourself). It's also important to be careful if every time you change the oil, the repair shop says you also need a new air filter. We expect drivers, in most cases, to spend more than a year and probably more than two years between air filter changes, depending on conditions and mileage. The air filter should be changed approximately every 6,000 to 10,000 miles and ideally at the same time as changing the oil.
At the very least, you should have it inspected. Taking a look costs nothing and you could avoid costly repairs later on. Replacement frequency varies by manufacturer and driving conditions. Some manufacturers say the filter needs to be changed every 15,000 miles while others say every two years or every 30,000 miles or more. The recommended interval for your vehicle will be detailed in the maintenance program section of your owner's manual.
Some will recommend every 45,000 miles while others recommend being closer to the 25,000 mile mark. And there are some companies that will even recommend that you change your cabin air filter every 15,000 miles if your driving conditions include busy roads, high temperatures or dusty unpaved road conditions. A dirty engine air filter will usually look dirty with dirt, dust or stains visible inside the folds. Air filter replacement can be part of a general tuning service that will help you get better mileage and performance out of your vehicle. When replacing the air filter, the new one doesn't have to be from your vehicle manufacturer or the same aftermarket brand that was there before but it does have to be the same size. The Department of Energy study found that electronic engine controls in modern vehicles are “sophisticated enough to prevent a clogged air filter from affecting the vehicle's fuel economy”.The owner's manual should show the location of yours and how to open its housing to remove the filter.
If your cabin air filter isn't replaced regularly, you run the risk of inhaling hazardous particles while you're inside the vehicle. The purpose of the engine air filter is to prevent dust, dirt and other environmental contaminants from entering the engine. In any case, it is a smart and proactive policy to inspect at least the air filter every 6,000 miles (9,656 kilometers). Vehicles also have a filter for the air that enters their heating ventilation and air conditioning systems but it has no relation to the engine air filter. Some people say it's excessive and that you should simply use your judgment to visually check the air filter and change it when it looks dirty. If the air conditioner blows weakly even with the highest fan setting, the filter may be clogged.
Harmful fumes, pollen particles, dust or harsh airborne chemicals can and will enter your vehicle's cabin if you don't have a fully functioning air filter. In acceleration races from 20 mph to 80 mph, cars like Dodge Charger were 6% slower with a clogged filter than with a clean one; Toyota Camry was 7% slower; Buick Lucerne was 12% slower. This shows how important it is to regularly check your engine's air filter and make sure it's clean. To sum up: Referring to your owner's manual is key when determining when your air filter needs replacing; generally this is every 12-15k miles but this can vary depending on your vehicle; keep track of how long it has been in place; inspect at least every 6k miles; replace when necessary; use judgment when visually checking; replace cabin air filters if driving conditions include busy roads/high temperatures/dusty unpaved roads; check for weak airflow from AC; replace with same size as original.