The Two Air Filters in Your Nissan Altima: Engine and Cabin

Your Nissan Altima is equipped with two separate air filters, each serving a critical and unique purpose. Understanding the difference is the first step to proper maintenance.

The ​engine air filter​ is located under the hood and is a key component of your vehicle's engine system. Its primary job is to clean the air entering the engine for combustion. By filtering out harmful particles like dust, dirt, pollen, and other debris, it ensures that your engine receives a steady flow of clean air. This is vital because your engine needs precise mixtures of air and fuel to operate efficiently. A clean engine air filter supports optimal horsepower, fuel economy, and protects internal components from abrasive contaminants .

The ​cabin air filter, typically located behind the glove compartment, is responsible for cleaning the air that enters the passenger cabin through the heating, ventilation, and air conditioning (HVAC) system. This filter traps pollutants such as dust, smoke, pollen, mold spores, and other allergens. A functioning cabin air filter significantly improves the air quality inside your vehicle, providing comfort for you and your passengers, especially those with allergies or respiratory sensitivities .

Why Regular Air Filter Replacement is Non-Negotiable

Replacing your Altima's air filters at recommended intervals is one of the easiest and most cost-effective ways to protect your investment.

A clogged ​engine air filter​ can have immediate negative effects. When airflow to the engine is restricted, it disrupts the air-fuel balance. This can result in a noticeable drop in engine performance, including reduced acceleration and power. You may also experience decreased fuel efficiency, meaning you'll spend more on gasoline. In severe cases, a dirty filter can even trigger the check engine light .

The consequences of a dirty ​cabin air filter​ are equally important. As it becomes clogged, airflow through the HVAC system is reduced. This forces the blower motor to work harder, which can strain the system and potentially lead to premature failure. The most immediate signs are weak airflow from the vents and the presence of unpleasant, musty odors inside the car. For drivers in dusty areas, a dirty cabin filter can lead to increased dust accumulation on the dashboard and interior surfaces .

Step-by-Step: Replacing Your Nissan Altima's Engine Air Filter

Replacing the engine air filter on most modern Nissan Altimas is a straightforward DIY task that requires no special tools and can be completed in about 10 minutes.

​For 2019-2024 Nissan Altima with the 2.5L I4 Engine:​​

This process is tool-free, thanks to a simple latch system .

1. ​Open the Hood:​​ Pull the hood release lever inside your car and secure the hood with the support rod.
2. ​Locate the Air Filter Box:​​ The rectangular air filter housing is situated on the driver's side (right side) of the engine bay, behind the headlight assembly .
3. ​Open the Housing:​​ On the front edge of the air box cover, you will find two silver metal latches. Flip both latches down to release them. Then, slide the entire cover forward slightly to disengage the two plastic tabs on the rear edge from their slots. You can then lift the cover open .
4. ​Remove the Old Filter:​​ Simply lift the old air filter out of the bottom half of the housing.
5. ​Clean the Housing:​​ Take a moment to inspect the bottom of the air box. Use a vacuum or a clean cloth to remove any accumulated debris or dirt .
6. ​Install the New Filter:​​ Place the new filter into the housing. It is designed to fit only one way, so it cannot be installed incorrectly. Ensure it sits flat and seals properly around the edges.
7. ​Close the Housing:​​ Lower the cover back onto the housing, making sure the rear tabs slide back into their slots. Push the cover back into position and flip the two metal latches up until they snap securely into place .

​General Steps for Other Altima Model Years:​​

The process is similar for other model years, though some may require a basic screwdriver.

1. ​Preparation:​​ Open and secure the hood.
2. ​Access the Box:​​ Locate the air filter box in the engine bay. You may need to use a Phillips-head screwdriver to remove screws securing the cover, or simply release spring clamps, depending on your model .
3. ​Replace the Filter:​​ Lift the cover, remove the old filter, clean the housing, and insert the new filter, ensuring it is oriented correctly .
4. ​Secure the Cover:​​ Reattach the cover by tightening the screws or securing the clamps. Make sure the seal is tight all around.

Step-by-Step: Replacing Your Nissan Altima's Cabin Air Filter

The cabin air filter is universally located behind the glove compartment, making access consistent across model years, including the 2025 Altima .

1. ​Empty the Glove Compartment:​​ Remove all contents from the glove box.
2. ​Access the Filter Compartment:​​ Open the glove compartment door. To lower it further, you may need to gently press in the stops on both sides of the glove box to allow it to drop down. Behind it, you will find a service panel that houses the filter .
3. ​Remove the Old Filter:​​ For the 2025 Altima, you may need a Phillips screwdriver to remove two retention screws from the service panel. Once the panel is off, you can slide the old filter out . On earlier models, the filter may be held in by a simple clip or cover that can be removed by hand .
4. ​Note the Airflow Direction:​​ Before inserting the new filter, check the old filter's orientation or look for an arrow on the new filter. This arrow must point in the direction of airflow, which is typically toward the rear of the vehicle. Installing it backwards can reduce effectiveness .
5. ​Install the New Filter:​​ Slide the new filter into the housing, ensuring it is seated properly.
6. ​Reassemble:​​ Replace the service panel and screws (if applicable), then push the glove compartment back into its original position until it clicks into place .

How to Choose the Right Replacement Air Filter

Selecting the correct filter is crucial for performance and compatibility. Here are the main types available:

• ​Standard Particulate Filters:​​ These are typically made of pleated paper or synthetic material and are designed to trap dust, pollen, and other larger particles. They are an economical choice for basic filtration .
• ​Activated Carbon Filters:​​ These filters include a layer of activated charcoal, which not only traps particles but also absorbs odors and harmful gases from the outside air, such as exhaust fumes. This is an excellent choice for urban driving or for those sensitive to smells .
• ​High-Efficiency Particulate Air (HEPA) Filters:​​ Some aftermarket options offer HEPA-level filtration, which is extremely effective at capturing microscopic allergens and pollutants. These are ideal for individuals with severe allergies or asthma .

When purchasing a filter, always check your vehicle's year, model, and engine size to ensure a perfect fit. You can choose between Original Equipment Manufacturer (OEM) parts from Nissan or high-quality aftermarket brands. Reputable aftermarket brands like Fram, Purolator, or K&N often provide comparable performance at a lower cost, but it's important to verify they meet OEM specifications .

Recommended Replacement Intervals and Costs

Adhering to a maintenance schedule will keep your Altima running smoothly.

• ​Engine Air Filter:​​ It is generally recommended to replace the engine air filter every ​15,000 to 30,000 miles. However, if you frequently drive in dusty or polluted conditions, you should inspect it more frequently and replace it as needed . For the 2024 Altima, the interval is extended to every 32,000 km (approximately 20,000 miles) .
• ​Cabin Air Filter:​​ The cabin air filter should be replaced more often, typically every ​12,000 to 15,000 miles, or once a year. Many owners choose to replace it before the summer season when the AC system is used most intensively .

The cost of a DIY replacement is relatively low. A quality engine or cabin air filter typically costs between ​​20 and 60. If you have the replacement done at a dealership or repair shop, the total cost can range from ​​100 to 200​ when factoring in labor . Performing this simple task yourself is a significant money-saver.

By understanding the role of both air filters and following this practical guide, you can easily maintain your Nissan Altima's performance, efficiency, and cabin comfort. Regular checks and timely replacements are a small investment that pays large dividends in the long-term health and value of your vehicle.