The air filter is a typical wear part in the car that should be changed regularly. Of course you can go to a workshop for the assembly, however, it does not have to be necessary since it is a job that also a layo could normally carry out without problems. Even if little or no cars are known. Following our simple instructions, changing the air filter is child’s play.

What is the purpose of changing the air filter?

The air filter is practically the “lungs” of the car. The engine needs air to run. Dirt and dust particles in the air could destroy the motor if it is not filtered. The air filter ensures that only clean air reaches the engine compartment. Over time, however, the fine pores can become clogged so no more air can pass through. Then the air-fuel mixture becomes increasingly greasy and the engine power decreases. Especially the acceleration is strongly impaired. Likewise, a problem with the air filter is a reason for not refusing the sticker of the vehicle’s technical inspection.

The new air filter – which one is best?

The dimensions that the new air filter should have are found in the vehicle’s instruction manual. However, it is often not necessary to consult it since many distributors can identify the correct product through the key number. The following models are offered:

– paper air filter, the most economical model. It works like the paper filter in a coffee machine and does a good job while it’s new. Its biggest disadvantage, however, is its useful life. Generally it does not usually last more than 15,000 kilometers. Those who drive little will still benefit from this economic model. Otherwise they are usually only a temporary solution.
– cotton or foam filters, the most used and preferred model of car manufacturers. This model is available at a moderate price and offers an acceptable service life of 30,000 kilometers. One of these should always be chosen during the vehicle’s warranty period as manufacturers often recommend this variant. Unfortunately there are large qualitative differences in terms of filtering performance, so the most economical variant should not always be relied upon. Mixed variants are also possible and their use has become more prevalent in recent years.
– oil-impregnated air filters, ideal for those who do many kilometers. These can be cleaned several times and re-impregnated with oil. Therefore, they sometimes reach a useful life of more than 60,000 kilometers, but they are also considerably more expensive. Expensive foam rubber is used almost exclusively as a manufacturing material. While there are rumors that such air filters can destroy the flowmeters of diesel vehicles, this is often the case if the part has not been manufactured or greased improperly.
– sports air filter, an exceptional case. It is placed directly on the intake manifold without a casing, which slightly increases the power but also increases the noise. Therefore, they must be accepted by the ITV. For day to day this filter model is generally not useful.

Step by step: change the air filter

For the change you will need the following tools:

the vehicle’s instruction manual, a screwdriver, some extension pliers, if applicable, a ring or open-end wrench, if applicable, a cloth, the new air filter

  • Step 0 : The first thing to do is open the hood (watch out for the fuses!) To locate the air filter box in the engine compartment. This is generally quite easy since it is usually in a very visible position and is also marked as “air filter” or with a symbol that indicates it. If you can’t find it, check the manual. There it is also indicated how it is opened.
  • Step 1 : If it is a diesel vehicle, you should first remove the plug from the quad meter that is directly connected to the air filter box.
  • Step 2 : Next you have to remove the suction tube, depending on the vehicle. To do this, press the hose clamp directly onto the spring with the extension pliers and push it back a little. The pressure exerted on the hose fitting is released. Then it can be set aside.
  • Step 3 : Open the air filter box. This is usually protected with two to four staples that can be released with a screwdriver. Below you can find screws or threads. If necessary, they must be unscrewed with the ring spanner or screwdriver.
  • Step 4 : Take out the old air filter. It can be disposed of with household garbage. If the air filter box is dirty, it should be cleaned with the cloth. Then place the new air filter. You can’t make too many mistakes here. They can usually only be placed in one direction.
  • Step 5 : First, the screws or threads are replaced. You can then secure the air filter box again with the clips.
  • Step 6 : Now place the suction hose in the corresponding opening, put the extension pliers back on the spring and push the hose clamps forward until it is a few millimeters apart. Release it and manually check if the clamp is tight.
  • Step 7 : On diesel vehicles you should put the plug of the flow meter back into the corresponding socket.
  • Step 8 : Now start the engine with the hood raised. Hit the accelerator a couple of times and pay attention to the noise. Get out of the car and check if the vehicle idles smoothly. If there is nothing to object, the change has been made successfully. Now you can close the hood.

Note: The assembly of an open sports air filter is generally considerably more complicated and involves the removal of the air filter box. Depending on the vehicle, there may be more peculiarities that will not be covered here. It is not advisable to carry out the assembly only if you are lazy in the matter. Sometimes it can even cause a decrease in performance. If you are interested in the subject, consult a professional workshop or visit reliable online information sources such as the Royal Automobile Club or the ITV.

Common mistakes and solutions

While changing an air filter is fairly straightforward and can be done normally without problems, failures and complications can always occur in this job. If you have problems after the change, read the following tips:

1. Irregular engine performance – If after changing the air filter you detect irregularities in the performance of your diesel vehicle, it is possible that the plug of the flow meter is not correctly seated. Shaking it a bit and / or reinserting it vigorously should solve the problem.

2. Noises while driving – If you hear strange noises on the first trip after the change, it is possible that the air filter box cover has not been fitted correctly. Either a staple is misplaced or a screw / thread is not tight. Here it is time to review the work.

Notice: Air filter – Modern vehicles often have their own fault diagnosis system. A warning about the air filter may appear on the screen after replacement. This normally restarts automatically when enough air reaches the combustion chamber again. It is also possible that the warning has to be deleted manually, if possible (see the instruction manual), or that a workshop has to be consulted for this.

3. Beeps coming from the engine compartment – If you hear a beep coming from the engine compartment during your first trip after the gearbox, it is possible that you have not positioned the suction hose correctly so air escapes through a small hole. In this case, carefully check the connection between the fitting and the hose. Retighten the hose clamp again if necessary and make sure the connection is tightly closed.