Measure and calculate the proper size and then verify the design It’s often taught that diagnosing a restrictive air filter is as simple as a visual inspection to see if it’s plugged. And, if the filter is dirty, replace it. Once this obvious defect is fixed, everything is assumed to work correctly. Could there be more to it?
What if the new air filter you installed is perfectly clean and still causing airflow issues? How should a technician test, diagnose, and solve this problem?