Coolant Flush
A maintenance service that drains old engine coolant, flushes out rust and scale, and refills the cooling system with fresh coolant.
A coolant flush (or cooling system flush) is a maintenance service that involves draining the old coolant (antifreeze) from a vehicle's radiator and engine block, flushing the system with water or cleaning agents to remove rust, scale, and sediment, and refilling it with a fresh mixture of coolant and distilled water.
Engine coolant does more than just prevent freezing and boiling; it contains chemical additives that protect internal metal components from corrosion, lubricate the water pump seal, and prevent scale buildup in the radiator core. Over time, these protective additives break down, and the coolant becomes acidic, which can corrode aluminum cylinder heads, eat through gaskets, and clog the radiator.
A clogged or corroded cooling system cannot efficiently transfer heat away from the engine, leading to overheating, water pump failure, or cabin heater core blockage. Signs that your vehicle needs a coolant flush include dark or rusty-looking coolant, coolant leaks, a sweet odor, or the engine running warmer than usual.
Most manufacturers recommend a coolant flush every 30,000 to 50,000 miles or every 3 to 5 years, depending on the type of coolant used (e.g., traditional green silicated coolant vs. long-life organic acid technology coolant).