What Are the Signs of a Bad Air Filter?


Nov 16th, 2021

What Are the Signs of a Bad Air Filter?

As a driver and car owner, you may only be concerned with supplying your car the right fuel. After gassing up, you then expect your car to return you the kilometres for every litre you pump in.

But is it that simple? Remember that the internal combustion process will only take place in an engine when there’s the right mix of fuel and clean air supplied at clockwork precision.

Yes, without clean air, there will be no combustion. So, to cut the chase, I’m going to focus on the car part that is responsible for ensuring the supply of clean air to the engine – and that is the air filter.

How Often Should I Change My Air Filter?

In average climate, air filters should be replaced about every 12 months or every 20,000 to 25,000 kilometres. However, there's no fixed answer to how often to change car air filter. In rural areas with a lot of dust and dirt or in cities with a fair bit of traffic, you’ll probably need to replace your air filter a bit more frequently.

It's best to inspect your engine air filter and assess if it's going bad.

Signs of a Bad Car Air Filter: How to Tell You Need a New Air Filter?

If you’re not sure whether it’s time to go ahead and replace your air filter, there are a few ways to tell. The following are five indicators that it’s time to change your air filter.

1. Your air filter looks dirty

It may seem like a no-brainer, but if you’ve never seen a car air filter or peeked under the hood before, you might not know what to look for. A dirty air filter will appear dark, either brown or black. 

In contrast, a new air filter is a lighter colour, closer to white. If it looks dark, it’s time to either clean your filter or swap it out for a brand new one.

You should also look at your filter to check for any other unusual contaminants or debris. Your filter shouldn’t be coated in dirt, dust, or rust.

2. You’re suddenly spending more for gas

You’ll experience better fuel economy with a clean and functional air filter. If it’s time to clean or replace your air filter, you might notice your car is less fuel efficient—up to 14 percent less. This specific issue effects older cars more than it effects new cars.

If your air filter is bad, fresh air will be blocked from entering the internal combustion chamber, and your car will compensate by using more fuel.

3. Your car doesn’t sound quite right when you start it

If your air filter is bad, your car might make a ‘coughing’ sound when you turn it on and when it’s idling. This happens when good, clean air can’t get inside the engine. You might also notice this unusual sound when you’re hitting the brakes.

4. Your spark plugs are damaged

If you ignore a bad air filter for too long, your spark plugs can get dirty and damaged, too. This might impact how your engine functions. It’s a good idea to check your air filter if you notice your spark plugs are dirty, and vice versa. You should clean both at the same time.

5. You’re noticing a strong smell of fuel or black smoke from your exhaust pipe

If your air filter isn’t working as it should, fuel may leak out and cause a plume of black smoke when you drive. You may also notice the smell of fuel is quite strong. These are two sure signs that something isn’t quite right, and your air filter is a likely culprit.

My Air Filter Is Bad, What Should I Do?

Replacing Car Air Filter

If you find out your air filter is bad, don’t worry. It’s easy to replace or clean a car air filter on your own. Also, if you’re not the handy type, you can find a mechanic who can help, too. Check out our directory for auto mechanics and car professionals.

To find out more about why you should keep your air filter clean, you can read our article about how a new air filter can improve an engine's performance

For maintaining other car parts, we invite you to bookmark our website now!