To repair a plastic radiator tank, you need to melt a nylon rod onto the damaged area. This can be done with a heat gun and welding machine. The repair process may take an hour or more, depending on the extent of the radiator damage.
- Drain the radiator
Drain the radiator's coolant until the liquid in the radiator is well below the damaged area. Dispose of the coolant in accordance with local regulations.
- Smooth the damaged area
Using a handheld grinder, smooth the area around the crack or hole to remove any jagged edges, and make a V-shaped indention over the damaged area.
- Melt a nylon rod over the damaged area
Use a heat gun, if possible, to soften the plastic nylon rod before melting it with a welder. The nylon rod should be melted into the V-shaped indentation with a welding machine. Some of the surrounding plastic on the radiator tank is likely to also melt. Mix the nylon with the additional plastic to form a stronger patch.
- Replace the coolant
After the patched area has cooled sufficiently, add the appropriate amount of coolant to the radiator, and test the patch by allowing the car's engine to run for several minutes.