What weight oil for diesel engine on motor home?

The weight of oil that is best for a diesel engine in a motor home depends on the make and model of the vehicle, as well as the location and climate in which it will be operated. Generally speaking, lighter oils are better for cold weather climates, while heavier oils are better for hot weather climates. For diesel engines in motor homes, it is typically recommended to use an oil that is SAE 15W-40 or SAE 10W-40. These oils are thick enough to provide adequate protection for the engine's components, while also being thin enough to flow easily in cold weather. It is always best to consult the manufacturer's recommendations for the specific vehicle and operating conditions.