BG Universal Cooling System Cleaner part number 540. Over time, rust and scale can build up in the cooling system. When deposits form on heat transfer surfaces, the engine loses the ability to effectively cool off. Buildup also restricts coolant flow, causing overheating and possible engine damage. BG Universal Cooling System Cleaner removes built-up scale, oil, and harsh mineral deposits. It also removes tough residues caused by oil fouling and coolant inhibitor breakdown. * Prevents overheating * Prevents cooling system damage * Extends cooling system life