Does My Car Really Need This Service ~ Engine Air Filter

Published on February 25, 2013 under Humble Mechanic
Dirty Engine Air filter

Top is a dirty air filter, the bottom is new

The engine air filter may be one of the most up sold items in the entire automotive world. But do you really need to have your air filter replaced? Today we will talk about some of the reasons why you may need a new engine air filter. We will also look at how you can be sure you actually need a new one.

What is the Engine Air Filter
It may come as a big surprise, but the engine air filter, filters AIR! Yes that is me being slightly sarcastic. There is really no need to over complicate what an air filter does. As air is pulled into the engine, the filter prevents debris from getting in the engine. It really is as simple as that.

Why is it important?
Well we answered this question above. The better question is, what happens when an air filter is bad. In this case bad means:

  • Dirty
    A dirty air filter will cause your engine to work harder. That can mean decreased MPG, and a reduction in power
  • Wrong, or improper fitment
    This can cause a number of issues. An air filter that does not fit properly can allow debris into the engine. It can also alter the flow of air into the engine. In some cases this can fool the sensor that monitors the flow of air into the engine. This can lead to a check engine light, and poor MPG.
  • Old and damaged
    An old air filter can actually come apart. On top of allowing debris in the engine, the engine can suck parts of the air filter in to the engine. This can cause damage to the engine.

How do I know if I need a new air filter
The great thing about air filters is it can be easy to tell if you need a new one.

  • Follow the owners book
    Most car manufacturers have a replacement interval. That interval is a great guideline to follow. Just remember that manufacturer inOtervals do not apply to everyone. For example if you live near the beach you need to replace your filter more often. Sand will clog a filter pretty fast.

    Dirty Engine Air filter

    Here, the top filter is new, and the bottom one is dirty

  • Visual inspection
    This is the only way to if you need a filter replacement. Here are a few things that you can look for:

    • Excessive dirt or sand
    • Oil saturation, this is can be the result of another problem. Do not just replace the filter if you find oil saturation.
    • Foreign objects, yep, it could be anything from a little critter to a Hot Wheel. None of those things belong on your air filter.

Do you REALLY need a new air filter?
This one depends on the condition of the air filter in your car. If the filter is dirty replace it. If it is clogged up, or falling apart replace it. Let’s say that a service place recommends you replace the filter because “it is dirty”. You should do what I always recommend and ask to see it. If the service department does not have the filter at the ready, they may not have inspected it. If they can show you the dirty filter from your car, ask to see a new one. This will let you see how bad the filter is. It will also let you check and make sure they are using the right filter.

If you have any further questions about replacing or inspecting an engine air filter, please post them in the comments below. Odds are if you have a question, tons of other folks have that same question. So please feel free to post them below.

I also want to take a second to thank you all for hanging in with me while I moved. It was a crazy busy, and stressful time. We are finally getting things back on track. I should be bringing the Cabby, aka Luv A Dub, home this week. I can’t wait to get back to working on her.

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  1. Pat ~ The Muscle Car Guy

    I always like the greasy finger or thumb print that many quick lube places put on it when they show it to you. Especially when it was pretty clean to begin with.
    Sure, it won’t matter much, but still, wash your hands before you touch something designed to keep the inside of an engine clean.

  2. Rosley

    Hi admin,

    In my opinion, replacing a dirty air filter will improve our car fuel economy by as much as 10% and protect our car engine. The air filter keeps out the impurities, which can damage our car engine in the long run.



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  4. NitaRice

    I had the oil changed this week. The fellow brought me an air filter from my car. It looked as if dirty oil having grit in it had been pored on it. Where the oil wasn’t on it , it was a pure white. Is it possible for a filter to have this on it with out the assistance of
    some one putting it on it. If so what is the likely problem?

  5. laura

    I was wondering if, when I get a tune up for my 2006 Mazda Miata, do they change the engine air filter? I noticed they recommended to change the engine air filter but also a tune up.
    Thank you,

  6. Patricia

    I just had to air filters changed and now it sounds like I have a fan or condenser running on just the passenger side. When prior I couldn’t hear my car running. Infiniti fx35

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