A dirty air filter can have a significant impact on the speed and performance of your car. When the air filter is clogged, it restricts the amount of clean air that reaches the engine, reducing its power and performance. Replacing the dirty engine air filter with a new, clean one can improve engine acceleration and fuel efficiency. Aftermarket air filters can lead to increases in engine performance and an increase in fuel mileage rating, although this may be more noticeable on older cars.
For newer models, some “performance” air filters may only make a negligible difference. A decrease in fuel consumption is often a sign that something is wrong. The air filter contributes to fuel efficiency, but a dirty filter can reduce oxygen flow. The vehicle must compensate for this by burning more fuel to compensate.
A dirty or damaged air filter limits the amount of air that flows into the car's engine, causing it to work harder and therefore consume more fuel. If you smell gasoline when you start the car, it's because not enough air enters the fuel injection system and excess unburned fuel comes out of the car through the exhaust pipe (hence the smell). Once an air filter is too clogged and no longer working, it can lead to decreased car performance and even engine damage. A visual inspection of your air filter in bright light will show a lot of dirt, but not all tiny particles can be easily seen.
Air filters are crucial to the performance of your car, and if not maintained in proper repair, it can cause setbacks to the longevity of your car. Many mechanics or dealers will allow you to purchase the filter on your own and take it with you for installation. If you're still not sure if it needs to be replaced, remove the filter and observe it during the day or use a flashlight to see how clogged it is. An air filter prevents dirt, debris, pollutants and road bugs from reaching the engine and ensures an adequate supply of air to the engine's combustion chamber.
With inadequate air supply, unburned fuel leaves the engine and may not produce smoke or flames in the process. An air cleaner is one of the most economical maintenance components to replace and you can do it yourself. Most manufacturers recommend replacing the air filter every 12,000 miles (approximately 19,000 km) or every 12 months, whichever comes first. It's important to ensure that the replacement air filter is designed for the exact make and model of your car.