A dirty air filter can obstruct the air supply to a car’s engine. But how often should one change a car air filter to prevent such a problem? WheelZine deals with this issue, as it gives you the signs and symptoms of a dirty car air filter.
Did You Know?
To consume 1 gallon of fuel, a car engine needs about 10,000 gallons of fresh air, which is cleaned by its air filter.
A car engine burns gas to generate power to drive the vehicle. Since burning anything needs air, this air is sucked in from outside and mixed with the fuel. This air-fuel mixture is then injected into the engine’s combustion chamber. But, ordinary air carries with it a lot of contaminants, like debris, dust particles, pollen, and pollutants, which can damage the engine. So, the air must be filtered of all these contaminants before it enters the engine. This function is performed by the car air filter. When such an important part gets clogged, it can ruin the performance of the car. Let us first see what the symptoms of a dirty air filter of a car are.
- Since this filter purifies air before it is sucked into the engine, a dirty one will block this air flow. This leads to a skewed air-fuel ratio, in which the proportion of fuel injected into the combustion chamber is higher, reducing fuel economy, even when the car is cruising on a highway.
- The engine contains pistons which move when the air-fuel mixture ignites inside the combustion chamber. This movement creates a vacuum in the chamber, which draws a fresh mixture, and the process continues. However, with a dirty filter, the vacuum is not able to draw sufficient quantity of air into the chamber. Moreover, pressing the pedal to accelerate draws additional fuel into the engine. The result is less power while accelerating, and rough performance. One might also experience engine hesitation while changing gears.
- As explained above, the blockage caused by a dirty air filter causes more fuel to be injected into the engine. This richer air-fuel ratio may cause fouling of the spark plug, leading to starting problems. Besides, if the filter is too clogged, it may completely block air flow, preventing the engine from starting at all. The spark plug may also be damaged by engine deposits caused by the rich air-fuel ratio.
- One might hear strange coughing and spitting noises coming from the engine, especially when the car is brought to a halt, like at a traffic junction. This may be a warning sign of air blockage caused by a dirty air filter.
- The rich air-fuel ratio caused ends up releasing more emissions from the exhaust, specifically that of carbon monoxide gas. So, if the car fails a tailpipe emission test, a dirty filter may be to blame.
- The ‘check engine’ light may come on resulting from the air blockage and engine deposits caused by a bad filter.
How to Check a Filter
Checking if the filter is dirty or not is often as easy as just taking a look at it. To do this, simply remove the filter from its housing (instructions given below). If it is clogged with dirt and grime, then that is a sure shot giveaway that it needs replacement. However, an air filter may often be clogged with contaminants like pollen and dust, which may not be visible on simple observation. To confirm this, just hold up the filter in sunlight or below a bright lamp. A pristine air filter should allow light to pass through it unhindered. If the light is getting blocked, this means that the ribs of the filter are clogged with dirt, and it should be replaced as soon as possible.
Why Change it?
- As mentioned above, a dirty air filter can lead to poor engine performance. However, it can also decrease the life of the engine. This is because, as the filter gets more clogged, its fibers may begin to get sucked into the engine by the vacuum created in its cylinders, which can damage the internal components like valves, bearings, and piston rings.
- Replacing a damaged air filter can offer several benefits, like improving gas mileage by up to 14%, and its acceleration by 11%, which varies with the model of the car. This can lead to savings of about 15 cents for every gallon of gas.
How to Replace a Filter
- To begin with, open the hood of the car.
- The air filter is located within a black, rectangular-shaped, plastic housing, which is of the size of a loaf of bread. It may be placed either on top or to the side of the engine, depending on the model.
- The housing may be held in place by either spring-loaded clips, which can be opened by hand or a screwdriver, or a wing nut in the middle.
- After opening the housing, remove the old air filter. Before replacing it with a new one, make sure that it is an identical replacement. Also, ensure that the ribs of the new filter face the same direction as the old one, which is mostly downwards.
- Reattach the cover on the housing.
- If you are unsure of the location of the car air filter, refer to the car manual. It will also have instructions about the frequency of air filter replacement for your car. Or else, take the car to a local auto spares store to take the services of a professional.
- Most auto spare stores charge between $20 – 30 for replacing one filter. With these simple steps, you can do the job at about one-third the cost. In fact, most people think that replacing the air filter is easier than even washing the car.
Most auto experts agree that air filters should be replaced every 12,000 miles, or after 12 months of use, whichever comes first. But this is for ideal conditions. If you live in an area where the air is laden with dust, such as along the beach, or drive frequently along dusty roads, then the frequency of replacement should be halved, as the air filter’s lifespan is significantly reduced. Moreover, the filter should be checked for clogging and damage every few months.