In order that the Siren may operate efficiently when required, and since internal combustion engines do not start as easily in cold weather as in warm weather, a heating element has been installed in the water jacket on the left side of the engine to insure quick starting in freezing temperature.

While this heater maintains the fluid in the cooling system at a far warmer temperature than would otherwise be possible, it has no effect on the lubricant in the oiling system. For proper lubrication, especially in cold weather and at the high speed to which the engine is immediately subjected when the Siren is started, the oil should be kept warm and as fluid as possible.

This can be accomplished by starting the engine at least 3 times a day and running it at idling speed, not to exceed 1000 R. P. M., until normal operating temperature of approximately 160° is reached as indicated by the temperature gauge located in the instrument group.

As a further protection for the Siren, in those areas where ice, snow, sleet, sand, or dust is encountered, it is recommended that a cover be made and the Siren kept covered at all times when not in use.