US Patent 10012133 Method and system for maintaining an engine coolant level

Methods and systems are provided for maintaining a desired engine coolant level and a relative glycol amount in the engine coolant by using water sourced from on-board vehicle systems. In one example, a method may include supplying water to the engine coolant reservoir in response to the engine coolant level decreasing below a threshold. Also, a relative glycol amount in the coolant may be maintained at a threshold amount by adding water to the coolant in response to a relative glycol increasing above the threshold.