The dust particles from the surrounding air that pass through the air filter of the engines can increase the wear of them. During the use of an air filter, it collects dust from the atmosphere, increasing the air flow restriction. The efficiency of an air filter increases while it is impregnated by impurities. The engine air filter is preventively replaced, according to the maintenance specifications mentioned by the manufacturer, not considering the real technical state of it. The paper shows the fact that the use of an air filter more than maintenance specifications can influence the power, torque and fuel consumption of the thermal spark engine that equips a hybrid vehicle. The clogging of the air filter will be gradually made.