Every vehicle needs oxygen for the combustion engine to function properly. Air filters maintain the engine free of dust, debris, or other small particles – such as sand, so that it can “breathe”.
You can find air filters in a variety of shapes and sizes, cylindrical, round, or panels. If you are looking to clean or replace your filter, you will find it near the front of the engine compartment under the bonnet. Some vehicles have large round air cleaners made of metal, which are hard to overlook.
How do I detect if my air filter needs cleaning?
There are many signs that it may be time to clean or replace your air filter. The most obvious one is that it looks dirty. Your vehicle will also let you know and it will show this in a variety of ways:
Your car uses more fuel than it used to. If you notice that you are spending more money at the petrol station, and not due to higher prices, it’s time to check your air filter.
The engine misfires, lurches, or has problems starting. If the engine does not receive enough air it will cause unburnt fuel to exit the engine and result in soot residue. The soot then collects on the spark plug which, as a result, cannot provide enough spark to ignite the air-fuel mixture.
If, when pressing the accelerator, you observe jerking or lurching. This could signal that your car is not getting enough air to perform properly.
The exhaust emits sooty, black smoke, or even flames. If your engine is not getting enough air supply, this can cause a part of the fuel not to burn completely. The fuel that is left unburnt then leaves through the exhaust pipe. If you notice your exhaust pipe emitting black smoke, you must clean or replace your filter. This condition is potentially dangerous and needs to be taken care of immediately.
If your fuel injection system or carburettor isn’t getting the oxygen it needs, the unburnt fuel will then be emitted through the exhaust pipe. Rather than seeing flames or smoke, you’ll notice a petrol odour – a clear sign that it’s time to replace the air filter.
The car has begun to make untypical noises. Normally, when your engine is turned on, but your car isn’t moving, it doesn’t make noises other than the humming of your engine. If you hear your car beginning to “cough” and “wheeze”, or notice an unusual amount of vibration then it’s time to clean or replace your filter.
How to make your air filter as good as new
Before working on your car, make sure that your engine has cooled down. Protective gear, such as goggles, face mask, and a pair of gloves is recommended to avoid injury.
Locate the filter and if it is enclosed in a cover, or housing, simply remove it with regular tools such as a screwdriver or spanner and put it aside. Do not let loose debris, dirt or dust enter the nearby intake or air box. If debris has fallen into the bottom of the air box, clean it out with a vacuum. Do not use compressed air – you may inadvertently blow debris around your engine.
Hold the filter over a garbage bin, or garbage bag and shake it to remove as much of the debris as possible. Using a vacuum cleaner, remove as much of the dirt that still remains on the filter. The most simple, and practical, way to do this is with a hand-held vacuum cleaner.
You can purchase a ready-made filter cleaner or you can make one yourself. Simply combine water with a mild laundry detergent or dish soap at a 2:1 ratio. Fill a spray bottle and seal it well, to avoid liquid leaking from the cap, and shake well before using. Now spray it onto and into the filter (depending on the shape) and let it soak in for a few minutes, but do not allow it to dry.
Next, scrub the filter with a soft-bristle brush making sure not to press down too hard, causing damage to the filter. You can use a toothbrush to scrub the small crevices the regular brush can’t reach. Make sure that you have scrubbed away all of the cleaning solution and residue before continuing to the next step.
Using a tap with running water, or a garden hose, carefully rinse the filter from the clean side going outwards, to push the dirt out. Be sure to keep the water pressure low to avoid damaging the filter, and continue until all of the cleaner has been removed. Get rid of excess water from the filter by carefully shaking it, and then allow it to dry completely.
If you have oil-coated filters, there is an extra step you must take. Use an air filter oil and spray the tops of each filter pleat, keeping the nozzle about three inches away. Make sure the filter is coated uniformly with the oil and allow the oil to be absorbed for about 20 minutes. With this step, it is essential that you allow the filter to completely dry before reinstalling it. Not doing this could cause your mass airflow sensor to malfunction. Now, reinstall the filter using the same tools you used to take out the filter. Take a second look to make sure that everything is reinstalled correctly.
Replacing a dirty filter
Locate the housing for your air filter and using common tools, such as a screwdriver, remove the screws that hold the housing together. Next, remove the cover to locate the filter, making sure that you don’t dislodge the hoses or stretch the wires. Make sure to note the position of the filter, so that you can install the new one correctly. This is the time when you should vacuum out any dirt or debris which may have fallen into the compartment. Install the new filter, making sure that the outer seal is fitted properly before closing the filter cover. Close the cover and replace the screws or clips.
How often do I need to clean or replace my car’s air filter?
It is recommended that you clean or replace your air filter after about 15,000 to 30,000 miles. This can differ depending on the vehicle and the environment you are driving in. If you often drive through the countryside along dusty roads, you may have to clean or replace your filter more frequently.