The purpose of the cabin filter is to keep the air inside of your vehicle fresh. The engine air filter keeps dust, sand and other contaminants out of your engine. There are several signs that you will notice if you need a cabin air filter or engine air filter change. Your heating and cooling system will make more noise if the cabin air filter needs to be changed. You may also notice a whistling sound coming from the cabin air intake duct. Additionally, you may notice musty odors and weak airflow.
Your vehicle likely needs a new engine air filter if the fuel efficiency has been reduced. A dirty engine air filter may also cause your vehicle to jerk. Other signs of a dirty engine air filter include strange engine noises, odors and black smoke coming from the exhaust pipe.