Many truck engines idle for very prolonged periods during cold winter temperature conditions to allow for warm-up and to keep the cab warm. Prolonged idling will reduce engine life and also waste fuel. Engines operate cooler while idling, and during long idle periods in winter's cold temperatures, moisture in the intake air can condense in the engine crankcase and produce corrosive sulfuric acid, which can attack soft bearing alloys. Long idling also contributes to increased soot and combustion contaminants, which will shorten the engine oil's life prematurely and can lead to excessive piston deposits, sludge formation and detrimental viscosity effects