There are two services related to replacing the coolant in an engine, draining and filling the system or a coolant flush. Flushing the coolant system is a bit more involved and serves to remove residue that is left behind when the coolant is merely drained and refilled. To perform a coolant flush, a technician will either connect a dedicated coolant flush machine or allow the engine’s water pump to do the work.
With either procedure, the old coolant is drained from the radiator. Clean water is forced through the cooling system, often with a special cleaning agent added (this might be done using a flush machine or by running the engine for a period of time). Once the system has been flushed, the water is drained. Although not required, a vacuum device might be installed (included on a flush machine) to remove air from the system before installing fresh coolant.
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