In some cars, Webasto is connected to bypass the engine, so it only heats the cabin. Here are the reasons for this: In some modern cars, the electronics monitor the external temperature and control the engine start-up. If Webasto heats the engine while parked, the electronics will still think the engine is cold, which can cause errors or prevent the engine from starting. Therefore, in such cars, Webasto is set up to heat only the cabin. The coolant is heated to a sufficiently high temperature, and when the engine is started, it will warm up quickly because the cooling system is already warm. The goal of Webasto is to ensure you get into a warm car. This goal will be fully achieved.