What Happens if Dirt Gets In Your Engine? | Ask the Experts at K&N

Dirt and grime on air filter

What would happen if you ran your vehicle without an air filter?

Your engine needs air for the combustion process. Ambient air is filled with particulate matter—dust, dirt, pollution, pollen, and so on. Without an air filter, that floating debris can contaminate and damage pistons, cylinder walls, and even the MAF sensor.

How does dirt damage cylinders and pistons?

If dirt or particles enter the cylinders, they can grind between the pistons and the cylinder walls, which will degrade both the piston rings and the walls themselves.


If the cylinder walls and piston rings wear down enough, the damage can prevent the rings from sealing—allowing combustion gas to leak into the crankcase (otherwise known as blow-by).

Damaged pistons can cause your engine to fail

If your engine is experiencing blow-by, the combustion efficiency will be significantly reduced—and you may notice smoke coming from the exhaust, sluggish acceleration, and an increase in the amount of oil that your car is guzzling. The cost of repair isn’t cheap, either—most piston replacements run in the thousands of dollars.


And you don’t want to wait until the engine damage is irreparable. With the average cost of engine replacement at over $7,000 (according to CarMD’s 2019 Vehicle Health Index™), it’s well worth the time to complete the routine maintenance that your vehicle manufacturer recommends.

What happens if dirt gets on a MAF sensor?

Your vehicle’s mass air flow (MAF) sensor calculates the amount of air entering the throttle body. If the MAF sensor is contaminated with dirt, it can begin running too rich (too much fuel, not enough air) or too lean (too much air, not enough fuel). Either issue can cause serious drivability issues.

Car on dusty desert road
Allowing dirt and dust in your engine can cause expensive damage

Prevent engine damage before it starts

Using a high-quality, efficient engine air filter—and servicing it regularly—can help protect your engine from damaging particles.


If you choose a disposable filter, it typically needs to be replaced approximately every 15,000 miles. K&N High-Flow Air Filters are washable and reusable, and designed to last for the entire lifespan of your vehicle.

Why use an oiled K&N air filter?

The oiled design of K&N air filters assists in “absorbing” dirt particles—and in turn helps incorporate those particles into the filter surface itself, which helps maintain the filter’s efficiency and ability to flow air. When tiny particles are captured and saturated with oil, they in turn can become tacky, allowing them to capture other particles. This same design has been protecting racers and daily drivers for over fifty years.

Don’t forget to install a high quality oil filter

Contaminated oil can cause severe and sometimes irreversible engine damage. An oil filter is designed to remove foreign particles from the circulating oil, and plays a critical function in engine protection.


If you don’t change your filter when your vehicle manufacturer recommends, or you install a poor quality filter, you can allow contaminated oil to degrade your engine components. If the oil gets dirty enough, your engine may break down completely.


Many late model car manufacturers recommend long service intervals of 5,000-10,000 miles, so be sure you are using a high-quality oil filter that can go the distance. K&N Performance Gold® oil filters are made with a heavy-duty canister and premium filter media to hold up to the demands of extended use.

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