What is the best air filter for a diesel engine?

When exploring diesel equipment filters for on- and off-highway equipment, it can be difficult to determine which filter is the best investment. In this short guide, we explore engine air filtration technology and help you understand what makes an air filter the best choice for your equipment. 

There are several types of filters that you’ll typically find in a diesel engine. Of course, you’ll find other types of filters located elsewhere, including the pre-filter for fuel, hydraulic filters, DEF/urea filters, and cabin air filters. When you’re looking at the engine itself, there is usually a secondary fuel filter, the transmission filter that removes particulates from the transmission fluid, one or two lube oil filters depending on the setup, and, our focus for this blog, the engine air filter. 

There are actually more than three air filter types, and it all comes down to what does the actual filtering. This is known as the filter media. Media can be made from cellulose (essentially paper), plastic, cotton, glass, foam, or a combination of materials. Some aftermarket diesel air filters are oiled, where a thin layer of oil is applied to catch contaminants, while others are dry. Another factor with engine air filters is whether they are replaceable or washable. 

It’s simple. The best engine air filter for a diesel engine is one with a high-quality media that will capture the contaminants and particulate matter that can wreak havoc in an engine. With large off-highway equipment, small particles can quickly lead to downtime and lost productivity. These contaminants can damage essential components like pistons, rings, and liners. These particles are measured in microns, and the typical air filter struggles with capturing particles in the zero to five micron size range. This is concerning, since 75% of contaminants are less than five microns in these environments. 

Here at Fleetguard, we’re passionate about protecting diesel engines from these tiny particles. We developed our NanoNet® media from nanofibers that can remove and retain contaminants at a submicron level. These nanofibers combined with our cellulose-based media with advanced pleat geometry, spacing, and stabilization results in engine protection that is unmatched in the air filter industry. 

Of course, there are other questions about air filter quality that many people ask. Let’s take a look at a few of the most frequently asked questions. 

Mishimoto Engineering found that oiled filters catch about 98% of contaminants while dry filters can catch up to 99% of contaminants due to the smaller micron size of the filter media. Oiling is an extra step that doesn’t necessarily translate to greater protection for your engine. 

It is best to avoid washable engine air filters. The savings these products offer are often lost in the time spent washing the filter and the poor performance of the filter if not washed completely or damaged while washing. In general, cleaning any filter (whether designated as washable or not) for reuse is not something we advise. Washing a filter can create tiny holes in the media and put extra wear and tear on the filter that can let in the dust and dirt you’re trying to prevent. The risk isn’t worth it, since replaceable filters are inexpensive when compared to the cost of the engine.

It depends on the quality of the filter and the recommended maintenance schedule. Different manufacturers will have their own suggestion for when to replace the air filter. Operating conditions will also affect the lifespan of the air filter. At Fleetguard, our air filters are an excellent option for your diesel equipment without compromising on engine protection due to our high quality, technologically advanced media.

We certainly think so! When you purchase Fleetguard filters, you’ll find the highest quality filters for every application. From air to fuel to oil and more, we’ve staked our reputation on filters that do exactly what we promise: protect your equipment, investments, and livelihood. In fact, we stand behind our filters with a warranty that is unmatched in the industry. If one of our filters fails and causes engine damage, we will completely reimburse you for the repair or replacement to get your engine back to like-new condition. Other filter manufacturers offer warranties that only pay up to the value of the engine at the time of failure, not the like-new condition. We stand behind our brand with this level of warranty because we know how much you depend on your engine functioning at peak performance. 

Explore our filter options to learn more about our offerings, or contact a Fleetguard dealer today to purchase or ask questions. If you are a dealer who would like to start providing Fleetguard filters, please contact us to learn more.