G37 Air Filter: The Essential Guide to Maintenance, Replacement, and Performance Benefits​

Replacing the G37 air filter is a critical, yet often overlooked, maintenance task that directly impacts your Infiniti G37's engine performance, fuel efficiency, and long-term reliability. For most owners, installing a new air filter every 15,000 to 30,000 miles is the single most cost-effective way to ensure optimal airflow, protect internal engine components from contaminants, and maintain the vehicle's responsive power delivery. Neglecting this simple component can lead to reduced gas mileage, sluggish acceleration, and potential engine wear over time. This guide provides a comprehensive, step-by-step overview of the G37 air filter, from selection and inspection to DIY replacement and expert maintenance tips, empowering you to make informed decisions for your vehicle's health.

​Understanding the Role of the Air Filter in Your Infiniti G37​

The air filter in your Infiniti G37 serves one primary function: to clean the air entering the engine's combustion chambers. Internal combustion engines require a precise mixture of air and fuel to operate efficiently. The air drawn from the outside environment contains dust, pollen, dirt, debris, and other particulate matter. If these contaminants enter the engine, they can act as abrasives, causing premature wear to sensitive parts like cylinder walls, pistons, and piston rings. The filter media, typically made of pleated paper or cotton gauze, traps these particles while allowing a steady flow of air. For the G37's VQ37VHR V6 engine, which is designed for both power and refinement, consistent clean airflow is non-negotiable. A clogged or dirty filter restricts this airflow, forcing the engine to work harder to draw air in. This imbalance in the air-fuel ratio can trigger a cascade of issues, including enriched fuel mixtures, incomplete combustion, and increased emissions. In modern engines with sophisticated sensors, restricted airflow can also cause the mass airflow sensor to provide incorrect data, further hindering performance.

​Types of Air Filters Available for the Infiniti G37​

When selecting a replacement air filter for your G37, you will encounter two main categories: disposable paper filters and reusable performance filters. Each type has distinct characteristics suited for different driving needs and owner preferences.

Disposable paper air filters are the original equipment manufacturer (OEM) standard. They are constructed from high-quality pleated paper enclosed in a rubber or plastic frame. These filters are designed for excellent filtration efficiency, capturing extremely fine particles. They are affordable, widely available from brands like FRAM, Bosch, or OEM Nissan/Infiniti parts suppliers, and are intended for direct replacement at recommended service intervals. Their primary advantage is consistent performance and high contaminant capture rate from new until they are replaced.

Reusable performance filters, most commonly marketed as "high-flow" or "low-restriction" filters, are typically made from layered cotton gauze or synthetic materials saturated with a special filtering oil. Brands like K&N are popular examples. These filters are housed in a durable, washable frame. The design philosophy emphasizes increased airflow potential over the filter's lifetime, which some manufacturers claim can lead to minor horsepower or throttle response gains. They are cleaned and re-oiled per the manufacturer's instructions rather than thrown away. It is crucial to understand that while they may offer a less restrictive path for air, their initial cost is higher, and they require meticulous maintenance. Improper oiling can lead to oil contaminating the mass airflow sensor, causing drivability issues. For daily driving, a high-quality paper filter is often the most practical and foolproof choice.

​How to Locate and Inspect the G37 Air Filter​

The air filter on the Infiniti G37 is housed within the air intake box, located in the engine bay. The process for inspection is straightforward and requires no special tools, making it an ideal first DIY task for any owner.

First, ensure the vehicle is parked on a level surface with the engine turned off and completely cool. Open the hood and secure it with the prop rod. The air filter box is a black plastic rectangular or trapezoidal container situated on the driver's side of the engine compartment. It is connected to a large intake hose. The box consists of two halves: a base and a lid. The lid is secured by a series of metal or plastic clips, typically four to six in number. To open the box, release these clips by pulling or flipping them upward. Some models may also have a screw or two near the front. Once all fasteners are disengaged, carefully lift the top half of the air box. You will now see the air filter resting in the lower half.

Remove the filter by lifting it straight out. Hold it up to a bright light source, such as the sun or a workshop lamp. Look through the filter media. A new or clean filter will allow a significant amount of light to pass through the pleats. If the pleats are packed with dirt, debris, or insects, and very little light is visible, the filter is dirty and requires replacement. Also, inspect the filter's sealing edges. If the rubber gasket is cracked, dried out, or damaged, the filter cannot seal properly, allowing unfiltered air to bypass the media. This makes replacement necessary even if the pleats look somewhat clean. If in doubt, compare it to a new filter. For most driving conditions, if you cannot remember the last time it was changed, it is likely time for a new one.

​Step-by-Step Guide to Replacing the G37 Air Filter​

Replacing the air filter is a simple sub-10-minute task. Here is a detailed, tool-free procedure. You will need only a new, correct replacement filter for your model year G37 sedan or coupe.

1. ​Preparation:​​ Park the car on a flat surface, turn off the ignition, and engage the parking brake. Allow the engine to cool. Gather your new air filter. It is good practice to briefly inspect the new filter for any obvious shipping damage before starting.

2. ​Open the Air Box:​​ As described in the inspection section, locate the air filter box in the engine bay. Identify and release all the clips securing the box lid. Use your fingers to pull the clips up and away from their latches. If there are any screws, use an appropriate screwdriver to remove them. Set any screws aside in a safe place.

3. ​Remove the Old Filter:​​ Once the lid is unsecured, lift it open. It may be connected to the mass airflow sensor or a hose; you can usually pivot it upward and rest it on another engine component without disconnecting anything. Do not force any attached hoses or wires. Reach into the lower half of the air box and lift the old filter out. Note its orientation—the shape is usually asymmetrical, with one side marked "UP" or having a specific contour.

4. ​Clean the Air Box:​​ This is a critical but often skipped step. Before installing the new filter, take a moment to inspect the inside of the empty air box. Use a microfiber cloth, a vacuum cleaner with a soft brush attachment, or compressed air to remove any loose dirt, leaves, or debris that has settled in the bottom of the box. Ensure the sealing surfaces where the filter sits are clean and dry. Do not use solvents or water that could drip into the intake tubing.

5. ​Install the New Filter:​​ Take your new filter and compare its shape and size to the old one to confirm it is the correct part. Place it into the lower half of the air box, ensuring it is seated perfectly. It must drop completely into the recessed area. Double-check that the filter's rubber sealing rim is flush with the mating surface of the air box all the way around. Improper seating is the main cause of post-replacement issues, as it allows dirty air to bypass the filter.

6. ​Close the Air Box:​​ Carefully lower the lid of the air box back onto the base. Ensure the filter is not pinched or displaced as you close it. Press down evenly on the lid until all the clips can be re-engaged. Snap each clip firmly back into its locked position. If there were screws, reinstall and tighten them snugly but do not overtighten. Give the box a visual once-over to confirm it is uniformly closed with no gaps.

7. ​Final Check:​​ Ensure no tools, rags, or the old filter are left in the engine bay. You can start the engine and let it idle for a minute. Listen for any unusual hissing or sucking sounds that might indicate the air box is not sealed properly. A normal, smooth idle confirms a successful installation.

​Recommended Replacement Intervals and Factors That Affect Them​

The official Infiniti recommended service interval for replacing the engine air filter in the G37 is typically every 30,000 miles under "normal" driving conditions, as outlined in the vehicle's maintenance schedule. However, this interval is a maximum guideline under ideal circumstances. Real-world conditions often necessitate more frequent changes.

"Normal" driving is defined as mostly highway mileage in relatively clean environments. For the vast majority of drivers, conditions are "severe." It is prudent to inspect the filter every 15,000 miles and plan for replacement between 15,000 and 25,000 miles. Several factors drastically accelerate the clogging of an air filter. Driving in areas with high dust or sand concentrations, such as dirt roads or construction zones, will saturate the filter much faster. Urban driving with frequent stop-and-go traffic and high pollen counts during spring can also shorten filter life. Vehicles used for frequent short trips where the engine rarely reaches full operating temperature may experience more condensation-related issues.

A simple visual inspection, as described earlier, is the most reliable method. If the filter appears dark, caked with debris, or damaged during an oil change or routine check, replace it regardless of mileage. The minor cost of a new air filter is insignificant compared to the potential fuel waste and engine strain caused by a clogged one. For those using performance oiled filters, the cleaning and re-oiling interval is different and specified by the filter manufacturer, often between 30,000 and 50,000 miles, but it requires a specific cleaning kit and careful application of the filter oil.

​How to Choose the Right Air Filter for Your G37​

Selecting the correct replacement filter involves more than just matching the part number. Consider your driving habits, performance goals, and maintenance willingness.

For the average daily driver seeking reliable, hassle-free operation, a high-quality OEM-specification paper filter is the best choice. Brands like WIX, Purolator, or Mahle offer excellent filtration efficiency and are readily available at auto parts stores. Ensure the part is listed for your specific G37 model year and body style (coupe or sedan), as there can be slight variations. These filters provide the protection the engine was designed for and are simply discarded at change time.

For enthusiasts or those in extremely dusty environments, a performance-oriented reusable filter from a reputable brand like K&N or aFe can be considered. The perceived benefits are a slight increase in intake sound and a potential for marginally improved high-RPM airflow. The key is to manage expectations; the power gains on an otherwise stock G37 are minimal. The major commitment is maintenance. You must purchase the specific cleaning and oiling kit and follow the instructions precisely. Over-oiling is a common mistake that can foul the mass airflow sensor, leading to check engine lights and poor idle. Under-oiling reduces filtration effectiveness. If you are not prepared for this extra step, a paper filter is superior.

Avoid no-name generic filters sold at deep discounts. Their filtration media or sealing gaskets may be substandard, potentially allowing harmful particles to pass through or failing to seal correctly. Always purchase from a reputable retailer or auto parts store. Reading verified customer reviews for specific part numbers can also provide real-world insight into fit and performance.

​Common Symptoms of a Dirty or Failing G37 Air Filter​

A deteriorating air filter does not fail suddenly; it causes a gradual decline in performance. Recognizing these symptoms early can save you money on fuel and prevent related issues.

The most common symptom is a noticeable decrease in fuel economy. As the filter becomes clogged, the engine's computer may enrich the fuel mixture to compensate for the perceived lack of air, burning more fuel for the same amount of work. If you see a sudden or gradual drop in miles per gallon, the air filter is a prime suspect. Reduced engine performance and sluggish acceleration, especially during overtaking or climbing hills, is another clear sign. The engine feels lazy and unresponsive as it struggles to breathe.

In severe cases, you may experience unusual engine sounds, such as a coughing or popping noise from the intake, or the engine may misfire under load. A very dirty filter can sometimes trigger a "Check Engine" light. The code is often related to the mass airflow (MAF) sensor readings being out of expected range due to the airflow disturbance. Visually, a black sooty residue on the throttle body or inside the intake tube downstream of the filter can indicate that the filter is no longer trapping contaminants effectively. Finally, in the most extreme neglect, a filthy filter can contribute to difficult starting or rough idling, as the air-fuel mixture becomes too rich or unstable.

​The Direct Benefits of Regular Air Filter Replacement​

Consistently replacing a dirty air filter with a clean one delivers immediate and long-term advantages for your G37 and your wallet.

The most tangible benefit for most drivers is the restoration of fuel efficiency. A clean filter allows the engine to operate at its designed air-fuel ratio, optimizing combustion. Owners often report a 1-3 MPG improvement after replacing a severely clogged filter, which translates to direct savings at the pump over thousands of miles. Engine performance and throttle response are also restored. The VQ37VHR engine is known for its linear power delivery, and a clean filter ensures it can breathe freely, providing the crisp acceleration the car is known for.

From a mechanical perspective, the primary benefit is engine protection. By ensuring only clean air enters the combustion chambers, you minimize abrasive wear on cylinder walls, piston rings, and valve guides. This directly contributes to prolonged engine life, sustained compression, and reduced oil consumption over the vehicle's lifetime. It also helps maintain lower emission levels by ensuring complete combustion, which is better for the environment and helps the vehicle pass emissions tests. Furthermore, a clean filter places less strain on the entire intake system, including the MAF sensor and throttle body, preventing related faults and maintenance costs. It is a classic example of preventative maintenance: a small, inexpensive part plays an outsized role in protecting a large, expensive engine.

​Frequently Asked Questions About the G37 Air Filter​

• ​Can I clean and reuse my standard paper air filter?​​ No. Disposable paper filters are not designed to be cleaned. Attempting to clean them with compressed air or tapping them can damage the fragile paper media, creating micro-tears that allow dirt to pass through. This defeats their purpose. They are designed for one-time use and replacement.

• ​Will a high-performance air filter increase my G37's horsepower significantly?​​ On a completely stock G37, the horsepower gains from a drop-in panel-style performance filter alone are negligible, typically less than 5 horsepower. The factory intake system is already quite efficient. Real performance gains require a comprehensive intake and exhaust system upgrade along with ECU tuning. The main advertised benefit of a reusable performance filter is increased airflow over its lifespan, not a peak power increase.

• ​How do I clean a reusable performance filter like a K&N?​​ You must use the specific cleaning kit from the manufacturer. The process generally involves: 1) Gently removing the filter from the air box. 2) Spraying the special cleaner on both sides and letting it soak. 3) Rinsing it from the inside out with low-pressure water to push dirt out, never from the outside in. 4) Letting it dry completely, away from heat or direct sun. 5) Applying the specific filter oil evenly and sparingly to the outer surface of the media. 6) Reinstalling only when the oil is tacky, not wet. Never use gasoline, solvents, or generic oils.

• ​Can a dirty air filter cause the check engine light to come on?​​ Yes, it is possible. A severely restricted filter can alter airflow enough to cause the mass airflow sensor (MAF) or oxygen sensors to report values outside the expected range, potentially triggering a diagnostic trouble code (DTC) and illuminating the check engine light. Replacing a dirty filter can sometimes resolve this.

• ​Is the cabin air filter the same as the engine air filter?​​ No, they are completely different parts. The engine air filter cleans air for the engine's combustion process. The cabin air filter, also called the pollen or interior filter, cleans the air entering the vehicle's ventilation and heating/air conditioning system for the occupants' comfort. They are located in different places (the cabin filter is usually behind the glove box) and serve separate functions. Both should be replaced periodically.

​Professional Tips and Cautions for G37 Air Filter Maintenance​

Beyond the basic replacement, a few expert practices can enhance the effectiveness of this simple task. First, always inspect the air intake duct and hose that connects the air box to the engine's throttle body. Look for any cracks, splits, or loose clamps. A leak in this hose after the filter allows unfiltered air to be sucked directly into the engine, nullifying the benefit of a new filter. Second, be extremely cautious around the mass airflow sensor (MAF), which is a sensitive electronic component often housed in the intake tube. Do not touch its delicate wires or attempt to clean it with inappropriate cleaners unless you are using a MAF-specific spray designed for the purpose. Disturbing it unnecessarily can cause expensive problems.

When installing the new filter, take an extra moment to run your finger around the entire sealing rim after it is seated. Ensure it feels even and flush with the air box base. If the lid does not close easily, do not force it. Open it again and reseat the filter; it is likely misaligned. For those in extremely dusty climates, consider a more frequent inspection schedule, perhaps every 10,000 miles. Keep a record of the replacement date and mileage in your vehicle's logbook. This helps establish a maintenance history and reminds you of the next due date. Finally, always dispose of the old paper filter responsibly; it is made of paper and metal and can often be recycled with other automotive materials where facilities exist.

​Conclusion: A Foundational Aspect of G37 Care​

Maintaining a clean air filter is one of the most fundamental and impactful services you can perform on your Infiniti G37. It requires minimal investment of time or money but pays substantial dividends in engine responsiveness, operating economy, and long-term durability. By understanding the signs of a clogged filter, following a simple replacement procedure, and choosing the correct part for your needs, you actively contribute to preserving the performance and refinement that define the G37 driving experience. Making air filter inspection a routine part of your vehicle check-up, such as during every other oil change, ensures this critical component never becomes an afterthought, allowing your engine to breathe easily for miles to come.