How to Fix a Plastic Radiator

Fixing a plastic radiator can buy time before a more expensive fix at a mechanic's shop.

The radiator in an automobile cools the engine by pushing coolant through the cooling system and by pulling heat away from the vehicle. Plastic radiators began to replace brass radiators in the 1990s, but they have some of the same challenges as older radiators, and unique problems of their own. If the radiator is not fixed, it could damage other parts of the engine.

Things You'll Need

• Radiator epoxy for plastic radiators
• Sandpaper
• Application brush
• Radiator hose
• Screwdriver
• Cooling system sealant
• Coolant

Instructions

1. Crank the engine and allow the vehicle to warm up, so that the radiator will move the coolant throughout the cooling system and the engine. Look for any dripping, spewing or seeping coolant and observe the location of the leak. Clean the surface of the radiator of any road debris, leaves or dirt that may be covering leaks. Typically, plastic radiators begin to malfunction due to leaks in the storage tanks, but the location of the leak dictates the method of repair, which could include a torn or ripped hose connected to the radiator.

2. Allow the engine to cool completely. Remove the metal ring holding the hose to the radiator. Firmly grasp the hose and remove it from the radiator. Repeat the same steps for the other end of the hose. Brush any debris from the openings left by the hose removal. Attach a new radiator hose to both ends and secure with the metal rings.

3. Drain the coolant from the radiator when the engine has cooled and disconnect the plastic radiator from the vehicle. Heat the area of the leak, melt the welding rod with an air-free plastic welder and place the melted rod over the leak. "Cold weld" products used for brass radiators are ineffective on plastic radiators.

   Or, use a plastic radiator repair kit with general purpose epoxy. Sand the leak area, brush the epoxy over the leak and allow it to set.

4. Open the radiator after the vehicle has cooled. Pour the powder or pellet coolant system sealant directly into the radiator opening and fill the remaining room with water or coolant. Run the engine until warm and drive for at least half and hour to get the system sealant to flow through the radiator and find the leak.

References

• Radiator Info: Stop Your Radiatior Leaking
• Radiator.Com: Radiator leak, Radiator Repair
• Auto Media: Car Radiator and Engine Coolant System Repair Tips