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Signs You Need a New Air Filter 

An engine air filter is a device that is designed to remove dust, dirt, and other contaminants from the air before it enters the engine of your vehicle. The filter is typically located in the air intake system of the engine, and its purpose is to prevent these contaminants from entering the combustion chamber and damaging the engine. It acts like a sieve to strain out particles from the air that would otherwise flow right into the intake in the air – things like bugs, leaves, pollen, dirt, and moisture.

An air filter can look like a short cylinder or a flat, rectangular box, or even like a cone. It’s made of pleated synthetic fibers in most cases, although some can contain natural cotton fibers or foam, sandwiched between plastic or metal mesh to maintain its shape and structure. A replacement air filter has a massive price range depending on what you drive, and it could be as little as $6 or over $150.

A clean air filter is essential for maintaining the efficiency and performance of the engine, and it is usually recommended to replace the air filter at regular intervals to ensure that it is functioning properly. In most cases, the air filter needs to be replaced once per year, and sometimes even more often than that. These are signs that your air filter is ready for a replacement or past due.

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Signs you need a new air filter 

The engine needs approximately two and a half times its displacement in air to run efficiently every minute. At idle, a 2.0-liter gas engine needs around 25 cubic feet of clean air per minute, and that goes up commensurately when the RPMs do. To get that much clean air into the engine, the air filter needs to allow plenty of air to flow through it.  

If it’s restricted by contaminants, you’ll begin to notice these symptoms of a dirty air filter. 

1. Dirty filter

When you inspect the air filter – which should be done at least every time the engine oil is changed – you might notice there’s debris stuck between the filter pleats or there’s dirt collecting on the material. Although some dirt and debris can be knocked loose or blown out with compressed air, the engine air filter should be replaced if you can’t see a light source through the pleated material.

2. Weird noises

An engine that’s starving for clean air will begin to make strange noises at times. It could be a sputtering sound, coughing, or popping from the engine area. The limited air supply flowing into the engine throws the air-fuel mixture out of whack and the engine runs inefficiently, which can cause the noises you hear. There isn’t enough air in the engine to thoroughly burn the fuel that’s been injected.

3. Check Engine Light

There isn’t a sensor on the air filter itself to indicate that it’s dirty, but there are other monitors that can insinuate decreased air intake. The mass air flow sensor, for example, could read lower levels of air entering the intake than normal, signalling potential air filter issues. The oxygen sensors in the exhaust can also determine that the combustion process isn’t on par, which is often caused by a plugged air filter. When these parameters are outside the normal range, it can trigger a Check Engine Light to come on.

4. Black smoke from exhaust

Black smoke from the tailpipe indicates an air-fuel mixture that’s too rich; that is, the proportion of fuel to air is too high. When that happens, the fuel doesn’t burn thoroughly before the exhaust stroke pushes it out of the combustion chamber, and the exhaust appears black, laden with unburned fuel.

5. Unburned fuel smell from exhaust

Similarly, a raw fuel smell from the exhaust is one of the common clogged air filter symptoms. If it’s badly blocked, the engine tries to compensate for a lack of performance by injecting more fuel to burn. When that happens and it doesn’t burn completely, it can exit the tailpipe and you’ll notice a fuel smell.

6. Fuel economy is noticeably lower

As the fuel system compensates for restricted airflow, it dumps more gas into the engine to attempt to produce the power you need to drive. The amount of fuel burned is noticeably more than normal, and fueling up more often might be an indication you should check the air filter’s condition.

7. Hesitation or stumbling on acceleration

Symptoms of a bad air filter can include decreased performance. If your car doesn’t accelerate smoothly, it bucks and burps when you’re cruising, or it stumbles and stalls when you’re decelerating, it can all point to a dirty air filter.

How to Change an Air Filter 

Most air filters take only a few minutes to remove and replace

  • Locate the air filter housing. 
  • Unclip or unscrew the housing to expose the air filter. 
  • Lift the old filter out. It might be a snug fit. 
  • Clean any dirt or debris from the housing to prevent the new filter from getting dirty prematurely. 
  • Slip the new air filter into place in the same orientation as the old one. 
  • Fasten the housing to finish up. 

To find the right air filter for the job, shop at AutoZone. Whether you shop online or in-store, choose the engine air filter that fits your vehicle using your vehicle information.  

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FAQ/People Also Ask 

How do I know if my air filter needs changing?

If you have noticeable performance or fuel efficiency decreases and/or the Check Engine Light is on, it could be due to a dirty air filter.

What are the symptoms of a dirty air filter?

A fuel smell, performance issues, decreased fuel economy, black exhaust smoke, engine noises, and/or a Check Engine Light on are signs you need a new air filter.

What happens if air filter is not replaced?

If the engine air filter isn’t changed routinely, it will starve the engine of clean air to burn. Along with operating less efficiently, you will have performance issues creep up in time.

How long do air filters actually last?

Air filter replacement intervals vary by operating conditions. Under normal circumstances, you’ll need to replace the engine air filter every year or 12,000 miles or so. If you’re in dusty or severe conditions, it could be every six months.

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