A heating and cooling system for an internal combustion engine comprising a heat storage circuit and a radiator circuit, and a method of controlling such a system are disclosed. The heat storage circuit comprises a heat storage container in which engine coolant is stored and allowed to flow into and out of. The radiator circuit comprises a radiator for flow of the engine coolant, and the radiator has a radiator inlet connected via an upstream radiator conduit to a coolant outlet of the engine, and a radiator outlet connected via a downstream radiator conduit to a coolant inlet of the engine. A bypass conduit is connected between the upstream radiator conduit and the downstream radiator conduit to allow coolant to bypass the radiator. A thermostat controlled valve is arranged in the upstream radiator conduit at a coolant outlet of the engine and connected to the bypass conduit.