The ​This comprehensive guide will walk you through everything you need to know about your 2018 Altima's air filters, including their importance, replacement intervals, DIY installation steps, and how to choose the right products for your vehicle.

Understanding Your 2018 Nissan Altima's Air Filters

Your 2018 Nissan Altima utilizes two separate air filtration systems, each serving a distinct purpose. The engine air filter is positioned under the hood and cleans the air entering the engine for combustion. A clean supply of air is vital for maintaining the proper air-fuel ratio, combustion efficiency, and overall engine performance. Meanwhile, the cabin air filter is typically located behind the glove compartment and purifies the air entering the passenger cabin through the HVAC system, removing dust, pollen, and other airborne particles to ensure a healthier environment for occupants .

These filters function as your vehicle's first line of defense against external contaminants. The engine air filter prevents abrasive particles like dirt, sand, and debris from entering the engine cylinders, where they could cause premature wear to sensitive components. The cabin air filter traps pollutants before they can circulate inside your vehicle, which is particularly important for individuals with allergies or respiratory issues. Both filters become less effective over time as they accumulate particles, eventually requiring replacement to maintain their protective functions .

When to Replace Your 2018 Nissan Altima Air Filters

Adhering to a proper replacement schedule is crucial for maintaining your Altima's performance and longevity. Nissan generally recommends replacing both air filters every 15,000 to 30,000 miles under normal driving conditions. However, this interval should be shortened to every 10,000-15,000 miles if you frequently drive in severe conditions such as dusty environments, heavy traffic areas, or regions with high pollution levels .

Several telltale signs indicate your air filters may need attention before reaching the recommended mileage:

​Engine Air Filter Symptoms:​​

• Reduced engine performance and sluggish acceleration
• Decreased fuel economy
• Unusual engine sounds or the illumination of the check engine light
• Black, sooty smoke from the exhaust or gas smells when starting the engine

​Cabin Air Filter Symptoms:​​

• Reduced airflow from the vents when climate control systems are activated
• Persistent unpleasant odors when using the HVAC system
• Increased dust accumulation on interior surfaces
• Whistling sounds coming from the dashboard area

Even without these symptoms, it's good practice to visually inspect your air filters during routine maintenance. A clean filter will appear off-white or white, while a dirty filter will be dark with accumulated debris. If you hold a questionable filter up to a light source and cannot see light passing through, it's definitely time for a replacement .

Step-by-Step Guide to Replacing Your 2018 Altima's Engine Air Filter

Replacing the engine air filter on your 2018 Nissan Altima is a straightforward maintenance task that can be completed in under 10 minutes with no special tools required. This DIY project can save you money while ensuring your engine receives the clean air it needs for optimal performance.

​Preparation:​​
Begin by purchasing the correct replacement filter for your specific Altima model. For the 2018 Altima with the standard 2.5L L4 engine, popular options include the A-Premium Engine Air Filter, KEDAKEJI Engine Air Filter, or EPAuto GP450, all designed to meet or exceed OEM specifications. Ensure the engine is cool and park your vehicle on a flat surface before beginning .

​Replacement Steps:​​

1. ​Locate the Air Filter Housing:​​ Open the hood and find the air filter housing, which is a rectangular black plastic box typically situated on the top or side of the engine compartment with a large hose connected to it .

2. ​Open the Housing:​​ The housing cover is secured by clips or screws. Gently unclip or unscrew these fasteners and lift off the top of the housing. Some models may require a flathead screwdriver for this step .

3. ​Remove the Old Filter:​​ Lift out the old air filter, taking note of its orientation. Be careful not to allow any debris from the old filter to fall into the air intake .

4. ​Clean the Housing:​​ Before installing the new filter, use a vacuum or damp cloth to clean any accumulated dirt or debris from the housing to prevent contamination .

5. ​Install the New Filter:​​ Place the new filter into the housing, ensuring it sits properly with the rubber rim facing up. Make certain it's seated correctly and that the sealing edges align properly with the housing .

6. ​Reassemble:​​ Replace the housing cover and securely fasten the clips or screws. Ensure the cover is properly sealed to prevent unfiltered air from entering the engine .

After installation, start your engine and listen for any unusual sounds that might indicate an improper seal. Take your vehicle for a test drive to ensure normal operation .

How to Replace the Cabin Air Filter in Your 2018 Nissan Altima

The cabin air filter in your 2018 Altima is located behind the glove compartment, making it equally accessible for DIY replacement. A fresh cabin air filter improves airflow, reduces odors, and enhances the air quality inside your vehicle.

​Replacement Process:​​

1. ​Access the Filter Location:​​ Begin by emptying your glove compartment. Gently press in on both sides of the glove box to lower it completely. You may need to detach the damper arm on the side to allow full access .

2. ​Remove the Filter Cover:​​ Behind the glove box, you'll find the cabin air filter cover. Gently pull this cover forward to reveal the filter compartment .

3. ​Remove the Old Filter:​​ Slide out the old filter, being cautious as debris may fall out during removal. Take note of the airflow direction arrow on the old filter, as the new filter must be installed with the same orientation .

4. ​Clean the Housing:​​ Use this opportunity to vacuum or wipe out any debris that has accumulated in the filter housing to ensure optimal performance .

5. ​Install the New Filter:​​ Insert the new cabin air filter into the housing, making sure the airflow arrow points in the correct direction (typically toward the interior of the vehicle) .

6. ​Reassemble:​​ Replace the filter cover and carefully reposition the glove compartment, reattaching any damper arms or stops that were detached during the process .

After replacement, turn on your vehicle's HVAC system to verify proper airflow and the absence of unusual noises. If unpleasant odors persist, you may need to have your air ducts professionally cleaned .

Choosing the Right Air Filter for Your 2018 Nissan Altima

Selecting the appropriate air filter for your Altima ensures optimal performance and protection. When choosing a replacement filter, consider your driving conditions, budget, and performance needs.

​Engine Air Filter Options:​​

• ​A-Premium Engine Air Filter:​​ This filter offers a perfect OEM-like fit with strong construction and adequate pleating for effective filtration. It's ideal for owners who want reliable performance without complications .

• ​KEDAKEJI Engine Air Filter:​​ Featuring a durable ABS plastic frame and deep pleats, this filter claims an extended service interval of up to 20,000 miles. It provides a snug fit and is suitable for drivers in dusty conditions .

• ​EPAuto GP450:​​ As a budget-friendly option, this filter delivers reliable performance for standard driving conditions. While slightly thinner than some competitors, it maintains good filtration quality .

• ​Genuine Nissan Nismo Air Filter:​​ For enhanced performance, especially if you have the 3.5L V6 engine, Nissan offers Nismo performance filters designed to improve airflow while maintaining filtration efficiency .

​Cabin Air Filter Types:​​

• ​Standard Pleated Paper Filters:​​ These basic filters effectively capture dust and debris but offer limited protection against allergens and odors .

• ​Activated Carbon Filters:​​ More advanced than standard filters, activated carbon options absorb odors, pollutants, and gases in addition to trapping particulate matter .

• ​HEPA Filters:​​ Providing the highest level of filtration, HEPA filters capture 99.97% of particles as small as 0.3 microns, making them ideal for allergy sufferers .

When selecting any air filter, always verify compatibility with your specific Altima model and engine type. Using genuine or high-quality aftermarket filters that meet OEM specifications ensures proper fit and performance .

The Importance of Regular Air Filter Maintenance

Maintaining clean air filters in your 2018 Nissan Altima delivers significant benefits that extend beyond basic vehicle operation. Regular replacement protects your investment and enhances your driving experience in multiple ways.

​Engine Performance and Longevity:​​ A clean engine air filter ensures optimal airflow to the engine, promoting efficient combustion. This translates to better acceleration, consistent power delivery, and reduced strain on engine components. Over time, this preventive maintenance can extend your engine's lifespan by preventing abrasive particles from causing internal wear .

​Fuel Efficiency:​​ When your engine receives adequate clean air, it maintains the proper air-fuel ratio for combustion. A clogged air filter restricts airflow, causing the engine to burn more fuel to compensate for the reduced oxygen. Replacing a dirty air filter can improve gas mileage by up to 10%, saving you money at the pump .

​Environmental Impact:​​ Properly maintained air filters contribute to reduced emissions by ensuring complete fuel combustion. A clean engine produces fewer hydrocarbons and other pollutants, minimizing your vehicle's environmental footprint .

​Cabin Comfort and Health:​​ Regular cabin air filter replacement directly impacts the air quality inside your vehicle. A fresh filter effectively removes pollen, dust, and other allergens from the air entering your cabin, which is particularly important for individuals with respiratory conditions or allergies. It also maintains proper HVAC system airflow, ensuring effective heating and cooling performance .

​Cost Savings:​​ While air filters represent a minimal expense, neglecting them can lead to costly repairs. A clogged engine air filter can cause sensor issues and increased component wear, while a dirty cabin air filter can strain the blower motor and other HVAC components. Regular replacement is a cost-effective way to avoid these potential problems .

Common Air Filter Myths and Misconceptions

Despite the straightforward nature of air filter maintenance, several misconceptions persist that can lead to improper care practices. Understanding the facts helps ensure you properly maintain your 2018 Altima.

​Myth 1: Air filters can be effectively cleaned and reused.​​
While some aftermarket performance filters are marketed as washable and reusable, standard paper air filters in most vehicles, including the Nissan Altima, are designed for replacement, not cleaning. Attempting to clean a disposable filter can damage the media and compromise its effectiveness .

​Myth 2: A dirty air filter doesn't affect fuel-injected engines.​​
Modern fuel-injected engines rely on sensors that adjust based on airflow. A restricted air filter can cause these systems to enrich the fuel mixture, reducing fuel economy regardless of the injection system .

​Myth 3: Cabin air filters only affect air conditioning performance.​​
While cabin filters significantly impact HVAC efficiency, they also play a crucial role in interior air quality. A clogged filter can allow harmful pollutants and allergens to enter your cabin, potentially affecting occupant health .

​Myth 4: All air filters are essentially the same.​​
Air filters vary significantly in materials, construction quality, and filtration efficiency. Investing in quality filters that meet or exceed OEM specifications ensures proper engine protection and cabin air quality .

​Myth 5: Air filter replacement requires professional service.​​
As demonstrated in this guide, both engine and cabin air filter replacement are straightforward procedures that most vehicle owners can confidently perform themselves with minimal time and tools .

Conclusion

Maintaining the air filters in your 2018 Nissan Altima is one of the simplest yet most impactful maintenance tasks you can perform. Regular replacement every 15,000 to 30,000 miles—or more frequently under severe conditions—ensures optimal engine performance, fuel efficiency, and cabin air quality. Whether you choose to replace these filters yourself or have a professional handle the task, understanding their importance and function empowers you to make informed decisions about your vehicle's care.

By adhering to the guidelines presented in this article, you can protect your Altima's engine from harmful contaminants, enjoy cleaner air inside your cabin, and potentially avoid costly repairs down the road. Remember to consult your owner's manual for model-specific recommendations and always use quality replacement filters that meet Nissan's specifications for your vehicle.