Apparatus and method of repairing a coolant system associated with an engine for a vehicle, including disconnecting a gooseneck connected to the engine and removing from the engine its thermostat; disconnecting a bottom radiator hose connected to the engine and flushing the engine with water; reconnecting the bottom radiator hose and reconnecting the gooseneck; refilling the engine's radiator with an antifreeze solution; opening a drain valve on the radiator and allowing a predetermined amount of coolant to drain out of the engine corresponding to a volume of a treatment composition to be added, the treatment composition comprising an aqueous silicate mixture comprising 50%-80% sodium silicate, based on a total amount of silicates in the mixture, and 50%-20% potassium silicate, based on the total amount of silicates in the mixture, the total amount of silicates comprising about 40%-50% of the mixture, a glycol in an amount of at least 10% by volume of the composition and the balance being water; starting the engine when the engine is cold, and turning on the engine's heater; adding the composition to the radiator of the engine while the engine is cold and idling; running the engine until the composition causes leakage and/or vapor in the engine's exhaust stream is substantially stopped; and stopping the engine and allowing the engine to cool.