A leaking car radiator should be repaired immediately to avoid complications. If you have never tried to fix a car radiator leak before, this is how you do it.
Required Tools and Materials
Pressure testing kit
Examine the whole cooling system. Check if the leaks are emanating from the radiator or if it is somewhere else in the system. You should also look at the seals, hoses, water pump and the engine. Defects in any of these components could lead to problems with the radiator.
If you think the problem is the radiator itself, top off the radiator and start the engine. Alternatively you can use the pressure test kit. Either method will let you know if the radiator is leaking or overheating.
To use the pressure tester, remove the radiator from the car. Put the radiator in water and look for bubbles. These bubbles indicate there is a leak.
To fix a car radiator leak, solder the broken components. Mix the epoxy and apply it on any pinholes or cracks on the radiator.
If the lower and upper hoses have leaks, they should be replaced. A small leak in the hose may be fixed with a seal, but this is only temporary. If the damage to the hose, radiator cap or coolant reservoir is extensive, they must be replaced.
Open up the radiator and put the cooling system in it. The sealant will consist of either pellets or powder. Either one will fuse with the coolant, removing the leaks. Put the coolant back in after you make the radiator repairs.
Get in the car and start the engine. You can idle high or run it. Keep going until the engine starts to heat. Carefully examine the radiator for signs of leaks.
Suggestions for Checking the Radiator
If the hole or damage is large, it will be easy to see. If not, look for other signs like green or orange discoloration. Another sign is a coolant deposit. If you still cannot see the defect, try removing the radiator. Do not forget to fill the cooling system after the repair job.
Do not attempt to use the car even if the leak is small. You need to fix a car radiator leak even if it is small. Ignoring the problem could make it worse. The radiator leak could even lead to more serious engine damage.