Express Lube locations

225 S Western Ave, Waupaca, WI 54981
1436 Neva Rd, Antigo, WI 54409
1133 Grand Ave, Rothschild, Wi 54474

Full service repair

323 S Western Ave, Waupaca, WI 54981
201 Central Bridge Street, Wausau, WI, 54401


6 Signs of a Bad Engine Air Filter

Your vehicle’s air filter allows the engine to breathe cleanly. If it’s dirty, more dust and debris can make their way into the engine, causing various issues. 

If you notice that your vehicle isn’t running properly, the engine air filter might be the cause. Here are some signs you need engine air filter replacement:

1. Dirty Air Filter

The best way to know if the air filter needs replacement is via visual inspection. Locate the air filter housing (typically a rectangular box near the engine), open it, and look at it.

The filter material should be almost white. If it’s dirty, clogged, or covered in debris, it’s time to replace it.

An auto mechanic showing an old engine air filter. Concept image of “6 Signs of a Bad Engine Air Filter” | Little Wolf Auto in Plover, WI.

2. Reduced Engine Performance

A clogged or dirty engine air filter can restrict airflow to the engine, resulting in reduced engine performance. You may notice a decrease in power, sluggish acceleration, or a general lack of responsiveness from your vehicle.

Most vehicles require 14.7 parts of air to 1 part of fuel. If you limit the air, the air/fuel mixture in the chamber won’t be correct. The engine will lose power, especially on acceleration.

3. Smoke and Fuel Odor

If the engine air filter is extremely dirty or clogged, it can disrupt the air-to-fuel ratio and result in incomplete combustion. This may cause dark gray or black smoke to emit from your vehicle’s exhaust pipe. You may also notice a gas smell.

The smoke and gas odor is there because there is too much fuel in the mixture or the spark plugs are dirty and not firing correctly. 

4. Poor Fuel Economy

When the engine air filter is dirty, the engine may not receive the proper amount of air for efficient combustion. This can lead to decreased fuel efficiency, causing your vehicle to consume more fuel than usual. Poor fuel economy due to dirty air filters tends to be more noticeable in older vehicles with a carburetor.

As a result, you might notice a decline in gas mileage. While the vehicle’s computer can adjust the mixture, if the air filter is too dirty, the computer won’t be able to make enough of an adjustment. 

5. Check Engine Light

Sometimes, a clogged engine air filter can trigger the check engine light on your vehicle’s dashboard. The onboard diagnostics system detects a problem with the air intake or combustion process and alerts you through the check engine light.

6. Strange Noises

Sometimes, a dirty air filter will cause the engine to cough or make popping noises. It could also cause the vehicle to vibrate. 

The vibration and noises happen because the dirty engine air filter is damaging the spark plugs. Ignoring the damaged spark plugs could cause the engine to misfire or eventually shut down.

So, in addition to changing the engine air filter, you will need to change the spark plugs in such a situation.

Is Your Engine Air Filter Due for Replacement?

Depending on your driving habits, you should change the air filter every 15,000 to 30,000 miles. If you drive in a city with a lot of smog or on gravel roads, you should change it every 15,000 miles or less. 

If unsure, check your vehicle’s manual to find the recommended interval for your specific make and model. You can also ask our team at Little Wolf Auto in Plover, WI for that service interval. Or go ahead and just get the service. 

Visit our express lube shop at 2550 Plover Road, Plover, WI 54467. You can also call us at (715) 883-5111 if you have inquiries.