How Filters Keep Your Car Clean Under the Hood

Your car has three different types of filters that work to keep the contaminants, debris, and impurities out of the fuel system, engine air supply system and car cabin air supply. They are the oil filter, air filter, and cabin air filter, respectively. If any of these filters is not functioning optimally, you will soon see that your car is not running, as it should. Thus, it is advisable to have your mechanic check them at regular intervals as recommended by the car manufacturer. Also, make sure you have them cleaned or replaced when they show clogging.

Air filter

  • What the air filter does: The air filter protects your engine from organic and inorganic debris that may enter it. These can be bugs, dirt, road debris, water or any other impurities the car might pick up on the road. The air filter also ensures that your engine gets the oxygen-rich air supply it needs to efficiently burn fuel and give you the maximum mileage per gallon of gasoline.

  • Symptoms of wear or clogging: If the air filter does not clean effectively, the engine has to work harder to burn fuel. Not only does it consume more fuel, but it also does not burn it completely. As a result, unburnt fuel makes its way out of the exhaust resulting in a black sooty smoke and even flames. You’ll also notice lower horsepower and acceleration, and lower fuel efficiency along with coughing sounds from the car engine. You might also have trouble starting up the engine because of sooty deposits on the spark plug.

  • When to change the air filter: It is advisable to replace the air filter every 10,000 to 15,000 miles or once in 12 months. However, if you live in a rural area or drive in dusty roads frequently, you might want to have it replaced every 6,000 miles.

Cabin air filter

  • What the cabin air filter does: The cabin air filter keeps the air inside the car cabin clean. It filters out dirt, dust, pollen, allergens, smoke, soot, mold spores, and other contaminants and prevents them from entering through the air-conditioning and heating vents.

  • Symptoms of wear or clogging: If the cabin air filter is not performing properly, you’ll notice a musty odor in the car and low pressure air flow from the car cabin vents. This is because of unfiltered air circulating in the cabin. You might also notice that the air-conditioning or heating is not very effective. A clogged car cabin air filter will result in your engine diverting power towards it and you’ll notice a lower horsepower.

  • When to change the cabin air filter: Consult the owner’s manual for directions on when to change the cabin air filter. Most manufacturers recommend that you change it every 12,000 to 15,000 miles or once in 12 months. Depending on the conditions in which you typically drive, you could have your mechanic check the cabin air filter every six months.

Fuel filter

  • What the fuel filter does: Essentially, the fuel filter works to protect your engine and keep it working. It cleans and filters the motor oil to remove the contaminants and metal shavings it gathers while circulating around the engine. An efficient fuel air filter can help prolong the time frame between motor oil changes. Most fuel filters come with a bypass valve that allows the motor oil to flow around the filter if it is too clogged and does not allow the free flow of oil.

  • Symptoms of wear or clogging: A worn out or clogged fuel filter will cause the engine to work harder to pump oil. This will result in lower fuel economy and slower acceleration. An insufficient motor oil supply can also cause friction in the engine’s vital parts, and overheating. Thus, your engine could stop functioning and the car could come to a complete halt.

  • When to change the fuel filter: The frequency with which you need to have the fuel filter replaced can depend on the conditions in which you drive and the kind of filter media or the membranes inside the fuel filter. Oil filters with cellulose media need replacing every 3,000 miles while those with synthetic media could need a change at every 5,000 to 7,000 miles. Oil filters with microglass media remain effective up to 10,000 miles. As an added precaution, have your mechanic check the fuel filter for clogging every time you take the car for maintenance.


The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Replace an Oil Filter Housing Gasket on Most Cars
Oil filter housing gaskets fail when the oil light is on, there is oil visibly dripping from the filter, or oil pressure is lower than normal.
The #1 Guide to Oil Change Coupon Codes (Updated 12/2020)
The most extensive guide for navigating oil change coupons and discounts.
What is the Oil Filter Housing all about?
How to diagnose and replace oil filter housing

Related questions

How can I change my oil filter
Hello. The filter (https://www.yourmechanic.com/services/change-oil-and-filter) is in the canister. You need to drain the oil and then unscrew the oil filter housing cap and pull out the filter from housing and replace all the O-rings that come with the filter and...
New oil filter replaced 5 days after oil change
Hey there. Yes it can. The reason it could have been leaking is because maybe something hit the filter while driving or the rubber seal on it didn't seal properly. You can change the filter (https://www.yourmechanic.com/article/what-causes-an-oil-filter-to-get-dirty) without changing the oil...
what is an good oil change interval to stick with this car
Toyota recommends changing the engine oil and filter on the 1999 4 cylinder Camry every 12,000 kilometers. Changing the oil, and performing other maintenance, using a mobile service such as YourMechanic (https://www.yourmechanic.com), can save you a lot of money. If...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com