Pe de alta parte, uitati ce zice cineva despre tinerea masinii la relanti : To summarise the negative effects of idling: Fuel combustion is incomplete, which leads to contamination of combustion chamber (glazing), spark plugs (wich reduces their effectiveness), exhaust system (including catalytic converter). Motor does not operate at optimal temperature, which leads to excessive condensation of water vapour in exhaust system, which leads to its corrosion (ergo premature replacement), and increased emissions. During idling engine does not work at its most efficient mode, and the fuel combustion is incomplete. That leads to glazing of combustion chamber and reducing effectiveness of spark plugs in petrol engines (plugs with heavy deposits can foul, and that can reduce fuel consumption by 4 to 5%). Also petrol can contaminate the motor oil which reduces its lubricating qualities (that could mean more frequent oil changes and/or increased wear on the engine). Also, as the engine runs at less than ideal operating temperature, which causes water vapour (a product of combustion) to accumulate in exhaust system (at proper temperature and at higher speed of exiting gasses caused by increased RPMs it clears out pretty good), which leads to corrosion. Also, idling produces up to 10–12% more emissions than driving for the same amount of petrol used due to incomplete combustion and ineffective operation of catalytic converter.