How Often Do You Need to Replace the Air Filter in a Car?

An internal combustion engine needs air to breath, the same as you or I. The more clean air, the better.

An engine air filter, which is different from the cabin air filter, traps solid pollutants so they don’t get into the engine. A dirty air filter can cause the dreaded Check Engine Light to come on and lead to all kinds of performance problems.

Over the years I’ve replaced many clogged, filthy and rotted air filters. One time, some creature built its nest in the air filter housing. The animal’s fur completely clogged the filter and the engine wouldn’t start!

Never drive without an air filter ($25) installed. Minuscule particles of dirt and rust from the air cleaner housing can make their way into an engine’s combustion chamber, ultimately tearing up the main bearings and crankshaft. That can ruin a $4,000 engine in short order.

What Is an Engine Air Filter?

A device, usually made from preservative- and solvent-treated pulp paper and folded into pleats, that traps damaging contaminants in the air. Some feature a stainless-steel grid backing that stiffens the filter, preventing premature seal failure.

An engine air filter not only cleans the air, but helps smother flames if an engine backfires.

Why Is Changing an Engine Air Filter Important?

A clean engine air filter provides:

• Better fuel economy, because it maintains the optimum air-to-fuel ratio.
• Improved acceleration and performance by allowing the maximum amount of air to enter the combustion chamber. It also increases mass air flow (MAF) sensor accuracy.
• Reduces tailpipe emissions.
• Prolongs engine life by keeping the smallest grit out of the engine. That prevents expensive engine parts from wearing prematurely.

How Often Should You Replace the Engine Air Filter?

Under normal driving conditions, most manufacturers recommend replacement every two years or 30,000 miles. But it really depends on your driving conditions.

Check the air filter every 12,000 miles, or at every oil change. Lightly tap the air filter on the ground to shake out any loose dust or dirt. Then give it the old-school “light” test. If you can see the glow from a flashlight or trouble light shining through the back side, it should still be OK.

But use common sense. If the filter looks off-color, the seal is weak or the paper/media has dried out, replace the filter.

You should also replace the filter at least once a year or sooner, and change the oil and filter every 5,000 miles or six months, under these circumstances:

• Your commute involves lots of stop-and-go driving or idling for long periods;
• You regularly drive in extremely dusty or sandy conditions;
• You live or work near a construction zone;
• You live in an area with constant high or low temperatures during your daily drive.

DIY vs. Pro Engine Air Filter Replacement: How Much Money Can You Save?

A lot. Before engine air filters were installed in environmentally sealed housings, most car repair shops installed replacement air filters for free!

Now it takes 15 minutes or longer to replace a dirty air filter because the housing may be buried under hoses, brackets or engine covers and secured with screws. Plus, engine sensors or other devices may need to be removed or disconnected. So, expect to pay $25 to $50 in labor, plus the marked-up price of the filter.

A repair shop may add $10 to $30 to the retail price of the filter. However, any reputable shop will stand by their work, making the extra cost a sensible investment if you’d rather pay than do it yourself.

If you’re interested in DIYing the job, replacing the air filter is easy on most vehicles. Just remember:

• To enhance air flow and protect the engine, buy a quality replacement air filter with a polyurethane frame that ensures a tight seal between the filter and its housing. When air filter shopping, beware: A manufacturer’s branded part can cost way more than its subsidiary branded part. A General Motors-branded air filter can cost more than $10 more than the exact same AC Delco air filter. They just have different packaging and part numbers.
• Take time to vacuum up any grit build-up around the air filter housing. Because it’s quick and easy, most mechanics use compressed air to blow gunk out of the air filter housing, possibly spreading dirt all over the engine compartment.