Heavy Duty Air Filter Cleaning Instructions

No Oil Required
K&N Hybrid Air Filter Technology

K&N's heavy duty line of washable commercial grade air filters are designed specifically for large turbo diesel engines, class 6-8 over-the-road trucks, agricultural and earth moving equipment, and diesel motor homes. These air filters do not require the use of oil like K&N air filters with cotton media.  K&N heavy duty air filter part numbers usually start with "38-".  To clean these air filters perform the steps below.

  1. REMOVE FILTER: Remove the air filter from the air filter housing. Handling with care, remove loose dirt and debris from the filter by tapping it with your hand and/or spraying it with compressed air. If compressed air is used, blow air from the clean side of the filter to the dirty side.
  2. APPLY CLEANER: Spray a generous amount of K&N Heavy Duty Air Filter Cleaner onto both sides of the filter, with the majority of it applied to the dirty side. Allow to soak in for 20 minutes. Do not allow it to dry on the air filter.

Standard Flow Air Filter Spray

Reverse Flow Air Filter Spray

  1. RINSE FILTER: Using a pressure washer or garden hose, begin by rinsing any large dirt particles off of the dirty side of the filter. Then rinse the filter element with cool or warm (not hot) water from the clean side out in order to flush the rest of the dirt out of the filter. Continue rinsing until the water flowing through the media is completely clear of any dirt or debris. Depending on the volume of dirt in the filter, a second or third application of cleaner and rinsing may be required.

Standard Flow Air Filter Rinse

Reverse Flow Air Filter Rinse

  1. DRY AND RE-INSTALL: After rinsing, gently shake off excess water. Allow filter to dry naturally, or use compressed air to speed the drying cycle. The filter should be dry, or just slightly damp before re-installing. Re-install the air filter element back into the air filter housing of the vehicle, following original installation instructions.

K&N Cleaning Video - Heavy Duty Synthetic Hybrid Air Filters