Changing your air filter regularly can improve the performance of your engine, reduce emissions and increase fuel efficiency.
The air filter is responsible for trapping dirt and debris; preventing it from reaching the engine. However, over time this filter becomes clogged, compromising the air flow. A certain amount of oxygen is needed for fuel to burn effectively, so driving your car with a blocked air filter can lead to ignition problems and, ultimately, damage to the engine.
How often to replace air filters
Car air filters are usually made from paper or cloth, and need to be replaced at least once a year. Reusable, washable foam or cotton air filters are also available, and these can be cleaned at home.
One of the most important reasons to change your air filter regularly is that a clean air filter provides better air flow to the engine, increasing engine performance. The other important job of the air filter is to trap foreign particles in the air, preventing them from entering the engine and causing abrasive damage to the metal components.
Air flow and the engine
An engine that uses internal combustion of fuel requires air to operate. Without the presence of oxygen, fuels like petrol and diesel can’t burn and power the engine. When the air filter becomes blocked, air cannot reach the engine easily, throwing off the balance of air to fuel. When this ratio is off, the fuel mix is said to run “too rich”, and this puts strain on the engine.
When to change the air filter
There are various signs that an air filter needs to be replaced. Often a decrease in fuel-efficiency is the first warning sign. Ignition problems – false starts, idling and stalling – are another symptom, caused by fouling of the spark plugs by poorly filtered air.
Ideally, air filters should be changed every 20,000 to 25,000 kilometres; more often if you frequently drive in dusty conditions, or stop-start traffic. Check your air filter every 10,000 kilometres to be safe.
Replacing the air filter
Changing the air filter on your car is relatively inexpensive, and easy to do yourself even if you have no experience as a mechanic.
Before you start, make sure that the replacement filter is designed for your make and model of car. On newer models of fuel-injection cars, the air filter is located at the top front or side of the engine. On these cars the air filter is rectangular, and is housed in a black plastic casing.
To check the filter, remove it completely and hold it up to a bright light. If the filter is opaque, it is full and needs to be replaced immediately. If your filter is reusable, you can remove it and vacuum it. Vacuum inside of the plastic casing too, as dirt will also accumulate here.