A method for repairing an automotive cooling system within an engine block of an engine includes installing at least a hollow repair stent and sealant. The repair stent may have a continuous cross-section or may be a hollow semi-cylinder defining a gap. The method includes draining coolant from the engine, removing the water pump from the engine without removing the timing chain cover of the engine, inserting the hollow repair stent including the sealant through the coolant passage, wherein the coolant passage extends through the timing chain cover into the engine, re-assembling the water pump to the engine and adding coolant to the engine so that the hollow repair stent remains in the engine.