If the antifreeze leaks from a car, the engine is likely to overheat. If the driver continues to operate the overheated vehicle, it is likely that major engine damage occurs. AA1Car.com says drivers should never ignore a hot warning light or temperature gauge that moves into the red.
The pressure from overheating puts additional stress on the radiator and hoses. If there are weak spots, either may burst. The steam in the cooling system causes damage to the plastic radiator end tanks.
Overheating the engine often results in a blown head gasket. The thermal stress causes the aluminum head to expand at a rate three times that of the cast iron block. This swelling occurs in the middle of the head, crushing the gasket, and allowing compression to leak between adjacent cylinders and coolant to flow into the cylinders.
As the engine grows hotter, the vehicle starts to detonate and lose power. The longer this continues, the greater the chances of damage to the pistons, rings and rod bearings. The heat causes the pistons to swell until they start to scrape against the cylinder walls, causing damage to both the piston and cylinder. The expansion also affects exhaust valves, causing them to stick or scuff their guides and leading to a loss of compression.