How to Distinguish Between Good and Bad Car Air Filters?

[DiJaxon]

Here are the methods to distinguish between good and bad air filters: 1. Water test - this is the most crucial and simplest method, especially for those without experience. Water is the best way to test the quality of an air filter. Place the air filter flat on the ground or a table and sprinkle some water on the filter paper: (1) If the water seeps into the filter paper within 5 minutes, it is made of cotton pulp paper and must not be used. (2) If the water seeps in within 2-5 hours, the filter is made of low-grade wood pulp paper. It can be used but will affect the air compressor's efficiency (higher electricity consumption, less air output). Due to their relatively lower price, such filters are commonly used in the air compressor industry despite their drawbacks. (3) If the water takes 12-15 hours to seep in, it is a mid-grade filter paper. Typically, better-quality domestic machine manufacturers use such filters as original equipment consumables. (4) If the water does not seep in even after 24 hours, it is definitely a high-grade filter paper, usually chosen by high-end machine manufacturers as original equipment consumables. 2. Check the filter paper's uniformity, light transmittance, and surface smoothness by holding it up to a light source. Uniform and fine texture, good light transmittance, and smooth surface indicate high filtration precision and good air permeability. 3. Examine the depth and number of pleats in the filter paper. A deeper and more pleated filter paper indicates a larger filtration area, which generally results in better air permeability.

[RafaelFitz]

When driving, I noticed that the difference between a good and bad air filter mainly lies in its appearance and condition. A new filter is usually pristine white with a soft, breathable texture; after use, the filter paper becomes dirty, especially turning from gray to black, and will shed dust or clog when lightly tapped. If there are small holes, tears, or if the filter has hardened or deformed, it’s definitely time for a replacement. Don’t wait until your car has issues—a poor-quality filter restricts airflow to the engine, leading to sluggish acceleration, increased fuel consumption, and in severe cases, accelerated component wear. I recommend checking it every six months or 10,000 kilometers by opening it up and testing with a phone flashlight: if light passes through easily, it’s still good; if not, it needs replacing. Spending a little extra on a quality filter saves you the hassle of costly repairs later.

[LaHeidi]

When I first started learning to drive, I didn't understand the importance of the air filter. It was only after experiencing symptoms that I realized. Slow engine starts, weak acceleration, or unusual exhaust colors are all signs of a bad filter; it gets clogged with dust, leading to incomplete combustion of the air-fuel mixture, and fuel consumption can spike by over 20%. A new filter is clean and breathable, ensuring smooth airflow. Regular checks are simple: remove the filter, and if it no longer feels smooth to the touch or is deformed, it's time to replace it; don't wait until a major repair costs you unnecessary money. It's recommended to replace it every 9,000 kilometers as per the car manual to avoid overloading the engine, saving you hassle and money in the long run. Once you make it a habit, your car will run as smoothly and steadily as new.

[KadenLee]

I enjoy DIY car maintenance. Judging the quality of an air filter is simple: take it out and check its light transmittance under sunlight or a lamp. A new filter allows light to pass through easily, appearing bright and unobstructed; a poor one blocks light, covered in gray-black spots or cracks, even shedding dust. Feel the surface—if it's rough, deformed, or loose, it's time to replace it. A bad filter not only affects performance but also strains the engine. Regular replacement prevents dust buildup; buy a reliable brand filter, and the job takes just minutes. Start with small tasks to protect your car's vital parts.