What does prolonged engine idle mainly cause?

Prolonged engine idling primarily leads to wet stacking, especially in diesel engines. Wet stacking occurs when unburnt fuel accumulates in the exhaust system, often due to incomplete combustion during extended idling periods. This can result in the fuel condensing and creating a build-up of liquid fuel in the exhaust. In diesel engines, this scenario is particularly common because these engines are designed to operate efficiently at higher loads. When idling for long durations, they don't reach their operating temperatures, which can contribute to this phenomenon.

Additionally, wet stacking can cause various issues, such as decreased engine performance and increased emissions. In severe cases, it may lead to damage within the exhaust system or other engine components if not addressed. This condition is a critical consideration for heavy-duty technicians when evaluating engine performance and maintenance strategies. Understanding the risks associated with prolonged idling can help technicians advise operators on the most efficient engine usage practices to prevent problems like wet stacking.