What should be set in accordance with departmental SOPs when it is necessary to leave the engine on in cold weather?

When it is necessary to leave an engine running in cold weather, the idle setting is particularly important to ensure the engine maintains a stable operating temperature and runs smoothly. In colder conditions, engines are prone to stalling or having difficulty starting. Setting the idle properly allows the engine to stay warm enough to avoid these issues, reducing the risk of engine problems when it is time to mobilize.

The idle setting also helps to ensure that the engine operates efficiently while consuming less fuel compared to a higher acceleration setting. This is critical in cold weather scenarios where fuel consumption can quickly escalate. Ensuring that the engine is at an appropriate idle speed helps to prevent wear and tear associated with abrupt cold starts or inconsistent operating temperatures.

In contrast, while the other options may have their importance in different contexts, they do not have the same direct impact on maintaining consistent engine performance in cold weather conditions.