CR26-31-1 Air Filter Part Number: The Ultimate Guide

The CR26-31-1 is a specific air filter part number manufactured by Fleetguard, a leading global brand in filtration technology. This part number refers to a high-performance, heavy-duty air filter cartridge designed primarily for use in heavy machinery, including on-highway trucks, off-highway equipment, and industrial power generation systems powered by Cummins engines, among others. Understanding this part number, its applications, proper maintenance schedule, and the critical role it plays in engine protection is essential for fleet managers, equipment owners, and maintenance technicians. Using the correct ​CR26-31-1​ air filter is not a mere suggestion but a fundamental requirement for ensuring optimal engine performance, maximizing fuel efficiency, and preventing catastrophic and expensive engine damage.

The CR26-31-1 part number is not a generic code; it is a precise identifier for a specific product with defined characteristics. Breaking it down, the "CR" series is Fleetguard's designation for their StrataPore™ media technology. This technology is a key differentiator. It represents a synthetic composite media that is highly efficient at capturing harmful dust and debris while maintaining excellent airflow and a high dust-holding capacity. This means the filter can last longer and protect the engine more effectively than many standard filters. The numbers "26-31" specify the physical dimensions and the design of the filter element. This standardized numbering system ensures that when you order a CR26-31-1, you receive a filter that will fit perfectly into the corresponding housing on your equipment, providing a secure seal. The final digit, "1," often indicates a specific iteration or version of the product within the Fleetguard catalog. It is crucial to use the exact part number specified by the equipment manufacturer or determined through a reliable cross-reference guide to guarantee compatibility and performance.

The primary function of the CR26-31-1 air filter, like all engine air filters, is to act as the engine's first line of defense. Internal combustion engines require a massive volume of air to operate. This air, however, is filled with contaminants such as dust, soot, pollen, and other abrasive particles. If these particles were allowed to enter the engine's combustion chambers, they would act like sandpaper, causing rapid wear to critical and expensive components. The most significant damage occurs to the cylinder walls, pistons, piston rings, and turbocharger bearings. This wear leads to a loss of engine compression, increased oil consumption, blue smoke from the exhaust, and a significant drop in power and fuel efficiency. Ultimately, unfiltered air can cause complete engine failure, resulting in downtime that can cost thousands of dollars per day and a repair bill that can reach tens of thousands of dollars. The ​CR26-31-1​ filter is engineered to trap over 99.9% of these harmful particles, providing a clean supply of air that is vital for the efficient combustion of fuel and the long-term health of the engine.

Knowing when to replace the CR26-31-1 air filter is critical for proactive maintenance. There is no single answer that applies to all situations, as the replacement interval depends heavily on the operating environment. The two primary methods for determining when a change is needed are service hour intervals and pressure restriction monitoring. Most equipment manufacturers provide a recommended service interval in the operator's manual, often based on hours of operation. For example, a typical recommendation might be to inspect the filter every 250 hours and replace it every 500 hours under normal conditions. However, "normal conditions" are rare for heavy-duty equipment. Operations in severely dusty environments—such as construction sites, mining pits, agricultural fields, or desert climates—will require much more frequent changes. In these conditions, a filter might become clogged in 100 hours or less.

The most accurate method for determining the need for replacement is by monitoring the air filter restriction gauge, also known as the restriction indicator. This gauge is typically mounted on the air filter housing or on the dashboard of the vehicle. It measures the vacuum pressure or restriction created when air tries to pass through the clogging filter. The gauge has a green (safe) zone, a yellow (warning) zone, and a red (action required) zone. When the restriction indicator enters the red zone, it signals that the filter is creating excessive restriction and must be replaced immediately. Continuing to operate an engine with a filter in the red zone starves the engine of air, leading to poor performance, excessive black smoke, and potential damage. It is a best practice to check the restriction gauge during your daily pre-trip inspection. Never ignore a restriction warning.

The process of replacing a CR26-31-1 air filter is generally straightforward, but it must be done with care to avoid introducing contaminants into the air intake system. Before starting, ensure you have the correct replacement filter, a clean rag, and a new gasket or seal if the housing requires one. The first step is to safely park the equipment on a level surface and engage the parking brake. Open the hood or access panel to locate the cylindrical air filter housing. Most housings are secured by a central wing nut or a band clamp. Carefully loosen and remove this fastener. Lift the cover off the housing. At this point, be extremely careful not to let any dirt from the dirty cover fall into the clean air intake tube. Remove the old ​CR26-31-1​ filter cartridge from the housing.

Before installing the new filter, you must thoroughly clean the housing. Use a clean, damp rag to wipe out the entire interior of the housing bowl and the cover. Ensure no debris remains. Inspect the housing for any cracks or damage that could compromise the seal. Next, take the new CR26-31-1 filter out of its plastic packaging. It is important to note that you should never pre-clean or tap the old filter in an attempt to reuse it. This practice can damage the media and will not restore its efficiency. Place the new filter into the housing, ensuring it sits flat and seats properly. Carefully reinstall the cover and tighten the wing nut or clamp securely, but do not over-tighten. Finally, reset the air filter restriction indicator on the dashboard or housing by pressing its button. It is also highly recommended to record the date, engine hours, and mileage of the filter change for your maintenance records.

One of the most common questions regarding the CR26-31-1 part number is about cross-referencing and compatible alternatives. Several other filter manufacturers produce equivalent filters that are designed to directly replace the Fleetguard CR26-31-1. These include major brands like Donaldson, Baldwin, Luber-finer, and Wix. Each brand will have its own unique part number for an equivalent product. For example, a common cross-reference for the CR26-31-1 is the Donaldson P821375 or the Baldwin PA2659. It is essential to use a reliable cross-reference chart or consult with a filtration specialist to confirm compatibility. While the physical dimensions may be identical, the filtration media technology and efficiency can vary between brands. Always ensure that any alternative you choose meets or exceeds the original equipment manufacturer's (OEM) specifications for your engine. Using a substandard filter can void engine warranties and lead to premature engine wear.

The consequences of neglecting air filter maintenance are severe and costly. The most immediate effect of a dirty, clogged filter is a reduction in engine power. The engine is starved of air, which disrupts the precise air-to-fuel ratio required for efficient combustion. This results in a loss of horsepower, sluggish acceleration, and black smoke emanating from the exhaust as unburned fuel is wasted. This condition, known as running "rich," directly leads to a significant decrease in fuel mileage. For a fleet of trucks, even a 5% decrease in fuel efficiency represents a massive and unnecessary operational expense over a year. Furthermore, the increased restriction caused by the dirty filter forces the turbocharger to work harder to draw air in, which can lead to premature turbo failure—a very expensive component to replace. The ultimate cost of neglect is major engine failure due to abrasive wear, a bill that can easily exceed the cost of hundreds of air filters.

Beyond just replacing the filter cartridge, there is another critical component to consider: the inner filter or "safety element." Some air intake systems are designed with a two-stage filtration system. The primary filter is the main workhorse, the CR26-31-1 cartridge. Inside the housing, surrounding the clean air outlet, there may be a smaller, secondary filter. This inner filter serves as a final backup. Its purpose is to capture any dust that might bypass a damaged or improperly sealed primary filter. This safety element is not designed to be replaced at every service interval. It is typically changed only if the primary filter is found to be damaged or if it has been exceeded its recommended service life, which is usually much longer than the primary filter, often around 500,000 miles or 5,000 hours. Neglecting to replace a contaminated safety element can negate the protection of a new primary filter.

Purchasing a genuine CR26-31-1 filter is as important as the replacement itself. The market is flooded with counterfeit filtration products that may look identical to the genuine Fleetguard filter but offer little to no protection. These counterfeit filters often use cheap, inefficient media and poorly constructed seals. They can fail prematurely, allowing dirt to pass through and destroy an engine. To avoid counterfeits, always purchase from authorized and reputable distributors. Look for the Fleetguard branding, holograms, and high-quality packaging. A genuine filter will have a precise part number stamp and a robust rubber end seal. If the price seems too good to be true, it probably is. The few dollars saved on a counterfeit filter are insignificant compared to the risk of a $20,000 engine rebuild.

Proper disposal of the used CR26-31-1 filter is also a consideration for environmentally responsible operations. Used air filters are considered solid waste. They should be handled in a way that minimizes dust exposure. Many facilities place the old filter directly into a plastic bag to contain the dust. It is then typically disposed of in a regular landfill. Some communities or waste management services may have specific guidelines, so it is always best to check local regulations. For operations with a large volume of used filters, recycling options may be available through specialized waste management companies. These companies can process the metal and paper components of the filter for recycling.

In summary, the ​CR26-31-1 air filter part number​ represents a critical component in the protection scheme of heavy-duty diesel engines. Its role in preventing abrasive wear, maintaining fuel efficiency, and ensuring peak engine performance cannot be overstated. Adhering to a strict maintenance schedule based on operating conditions and monitoring the restriction gauge is the key to maximizing engine life and minimizing operating costs. Always use a genuine or certified equivalent filter and follow proper installation procedures to ensure a perfect seal. By giving the CR26-31-1 air filter the attention it deserves, you are making a smart investment in the longevity and reliability of your valuable equipment.