- Car Care & Maintenance
How to Check and Replace a Car Air Filter
Do you give your car air filter the credit and attention it deserves?
The air filter prevents damaging particles from going into the engine. But as vehicle millage increases, so the amount of particles trapped around your air filter. Eventually, the filter element clogs up. This increases emissions, engine deposits and fuel consumption; reduces engine power and makes it run roughly. And it makes your engine work much harder too.
According to the US Department of Energy, an obstructed air filter reduces engine power and fuel economy by as much as 11 percent.
And that's not all. Once the air filter wears out, airborne contaminants can find their way into the engine. These particles work as sand paper inside the engine, scratching pistons, cylinders, cylinder walls, piston rings, and the air flow sensor, if equipped. Next thing you know, your engine is leaking oil and compression, and you got a very expensive repair that could've been avoided by spending a few dollars at the right moment.
So replace your car air filter at the recommended intervals or sooner.
Here, we'll see how to check and replace the air filter on your vehicle, highlighting some important key steps so that you do a successful air-filter replacement job.
Effects of a Plugged Up Air Filter
Reduced engine power
Accumulation of engine deposits
Increased fuel consumption
How to Check the Air Filter
Most car manufacturers recommend replacing the air filter at the 10,000 or 15,000 miles mark — about once a year. Others set the service interval at 30,000 miles or higher, depending on the vehicle model. But if you have to drive on dirt roads regularly, drive around dusty areas, or within the city making frequent stops, you'll need to change the air filter sooner.
Here's how to check your car air filter.
1. Open the hood.
* On older vehicle models with a carburetor or Throttle Body Injection (TBI) system, look for a large drum or oval shaped metal case towards the top and back of the engine. This is the air filter housing.
* Modern vehicles use some type of fuel injection system. On these models, look for a black, plastic air cleaner assembly on top of the engine. You'll find the filter housing (case) between the intake (big duct) tube — towards the front of the engine compartment — and the throttle body assembly.
2. Remove the lid off the air filter housing by unscrewing the one or two wing nuts, or flipping the spring clips at the side of the assembly. Then, lift off the cover.
You may have to disconnect the big, intake tube first to remove the lid from the air cleaner housing. Still, on some car models you need to use a standard or Phillips screwdriver, open-end wrench or pliers to gain access to the air filter.
3. Watch out for screws, dirt, or small parts that may fall through the carburetor, TBI plate, or air inlet. If necessary, place a clean rag on the plates or inlet space to prevent this.
4. The filter is usually flat, elongated or round, with a paper element as the filter media, held by an orange or red plastic frame. Lift out the filter from the housing.
Change the air filter at the recommended interval to prevent engine performance and fuel system issues.
5. If your car uses a flat, pleated air filter, note in which direction the filter sits so that you replace it or install a new one correctly.
6. Carefully check the housing and connecting duct or hoses for damage like cracks and burns. Fix or replace components as necessary.
7. Remove dust and debris from the cover and filter housing using a damp rag and a vacuum cleaner, if necessary. On models with a plastic housing, handle the lid and casing with care during your cleaning procedure. It's easy to damage plastic components and end up with an air leak that will lead to engine damage if dust, dirt and other foreign particles find their way into the combustion chambers.
8. Examine the filter element for tears, signs of water or oil. If you find any of these, replace it.
9. Using a bright flashlight, position the light behind the filter. The light should shine through the filter. It's okay if the filter has lost some of its original color. However, if the light cant' go through the filter and the element looks dark, you need to replace it.
Also, if your filter is due for replacement, according to your car manufacturer, replace the filter. Look up the service schedule for your filter in your vehicle repair manual. If you don't have one, buy an aftermarket repair manual at your local auto parts store or online.
By the way, don't try to knock off dirt or dust by banging the filter on the floor. You'll never free enough trapped particles attached to the filter element. Besides, reusing a blocked filter will only lead to poor air flow and engine performance.
How to Change the Air Filter
1. Compare the old filter with the new one. They should have the same physical size and configuration.
Note that there's nothing wrong with using an inexpensive air filter as long as you replace it at its due time. However, if you want to upgrade, use a filter with a high percentage of synthetic fiber or treated with resin, which makes it more resistant to moisture.
Do you frequently drive on dirt roads or dusty areas? Do you drive 99 percent of the time within the city? Consider using a foam air filter type. These filters are treated with oil and have a higher dust absorption rate than regular paper filters.
2. Once the inside of the filter housing dries out, install the new filter. Some filters have one side marked TOP. This side should face up when you install it in the housing.
3. Replace the housing cover and, this is important, make sure that it seals properly. Otherwise, you'll have an air leak and dust particles will find their way into the engine with catastrophic results in the long run.
4. Replace the intake tube, if you have to remove it. Secure the lid and other components with the wing nuts, clips or screws.
A simple air filter change at its due time will have a positive impact. Engine performance and power, fuel economy and service life, all will improve. Plus fewer repairs to deal with later on. And, since an air filter doesn't cost that much and takes just a few minutes to replace, you're getting a lot in return just by paying attention and servicing this simple component. So take a moment to check the air filter at each oil change, whenever you are performing some maintenance on your vehicle, or need to open the hood to inspect something. And definitely, replace the filter at your manufacturer recommended schedule.