Advocate III
Here's some interesting info from Motor Vehicle Maintenance and Repair - Is Idling Bad For Your Engine
Aside from financial and environmental considerations, U.S. and Canadian governmental agencies say that idling produces various negative effects on engine components.
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.
As I mentioned above, public service vehicles have heavier duty engines and maintenance and mechanical staff available. You can count on their vehicles being maintained and worked on more regularly than the common consumer's car. Their vehicles are also not expected to last as long, in most cases, as consumer vehicles as they know they're going to rotate them out for new vehicles within a couple years. I would not use the fact that cops and ambulance drivers may idle their vehicles for long periods as excuse to do the same with your own.
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Aside from financial and environmental considerations, U.S. and Canadian governmental agencies say that idling produces various negative effects on engine components.
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.
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