How to Repair a Crack in a Radiator

Many radiators are being made from plastic due to the high melting point of the material. Using nylon blended with glass fibers, the plastic radiators are less expensive to make and more durable than the old steel radiators. Occasionally, the plastic radiators may develop a crack in the body due to weather conditions or usage. You can repair the cracks in about two or three hours rather than having to replace the entire radiator.

Instructions

1

Locate the crack in the plastic radiator and take the cap off the top of the radiator.

2

Find the drain plug at the bottom of the radiator tank, and place a drain pan on the ground beneath the plug.

3

Open the drain plug with an open-end wrench and allow the coolant to drain into the drain pan.

4

Burn a V-groove along the crack in the radiator, using the tip of a plastic welder to give a better surface for repairing the radiator crack.

5

Preheat the plastic around the crack in the radiator by using a heat gun on the surface until the plastic takes on a glossy look, and let the plastic sit for a minute or two.

6

Heat the crack with a heat gun for another five minutes to allow the heat to soak all the way through the radiator near the crack.

7

Lay a nylon welding rod at the end of the crack that you are repairing, and use an airless plastic welder, heating the rod and melting the welding rod about an inch at a time. Lay a seam inside the crack and work the seam into the crack with the melting rod.

8

Repeat Step 7, making a thin seam of nylon on top of the last seam until the crack in the radiator is closed up and the V-groove is filled.

9

Smooth out the weld so that it is flush with the face of the radiator using the plastic welder to heat the plastic and spread it out.

10

Let the radiator set for a couple hours to solidify the weld and then close the drain valve on the bottom of the tank with an open-end wrench and fill the radiator with coolant.

11

Place the cap back on the radiator and remove the drain pan from under the vehicle, taking the drained coolant to your local recycling center or auto parts store.