How to Repair Your Leaking Radiator

Some radiator repair can be done by the consumer, avoiding the high cost of mechanics.

A leaking radiator can occur in any car, including a relatively new one. In older cars, the radiator can corrode, eventually leaking coolant and causing the vehicle to overheat. In newer vehicles, bad seals in the water pump can cause leaking of coolant. In any car, hoses can become worn and leak or seals can go bad, causing the engine to overheat and the radiator to leak. Once the coolant begins to leak, the pressure in the radiator drops and overheating makes the radiator even more prone to leaking.

Things You'll Need

• Radiator anti-leak solution
• Wrench
• Screwdriver
• Coolant
• Solder
• Soldering Iron

Instructions

Identify the Leak

1. Inspect the entire cooling system to locate leaks that are either in the radiator or elsewhere in the system, which could eventually cause the radiator to leak. Check the radiator, the engine, the water pump, all hoses and seals for signs of leaking.

   Alternatively, pressure test the radiator with either a pressure testing kit or by topping off the radiator and running the engine to see if it overheats or if the radiator leaks.

2. Replace the leaking part, if it is visible, including upper and lower hoses, the coolant reservoir and even the radiator cap. A small hole in a hose may seem easy to repair, but a temporary seal will not hold it for long. A leaky hose needs to be repaired.

3. Solder any broken pieces of the radiator back in place. Use an epoxy glue to seal any cracks or pinholes in the radiator.

4. Open the radiator, and pour in a bottle of cooling system sealant. Cooling system sealant comes in powder form and pellets, both of which mix with the coolant, flow into leaks (such as gasket tears) and swell to fill the leak.

5. After making any repairs to the radiator, or any other part of the cooling system, replace the coolant lost due to the repair or the leak.

6. Start the vehicle, and either run at high idle until the engine heats, or drive it to warm the car, checking to see if the radiator still overheats.

Tips & Warnings

• These steps are for small leaks to the cooling system. If they do not work, you will either need to take the radiator to a mechanic for repair, or replace it altogether.

References

• AA1Car.com "How to Find & Fix Coolant Leaks"
• Auto Media: Car Radiator and Engine Coolant System Repair Tips
• Do It Yourself: How to Repair a Radiator Leak