Plastic Radiator Repair: How to Fix a Cracked Plastic Radiator

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What You'll Need
Soldering iron
black tie wraps
tooth brush
hair dryer
marker or tape

Plastic radiator repair is performed at most auto body shops, but you have to pay for expensive labor. Fixing cracks in your radiator is a relatively quick and easy job, and you will save on your hard earned cash by simply locating the crack, preparing the area, and fixing the problem yourself.

There are various parts of the plastic radiator that can leak: you may spot a crack on the hose or the body of the radiator itself. Before you get to the actual repair, you may want to examine the fittings that lead to the radiator. In case the leak is coming from the radiator, put your old clothes on, roll up sleeves, and follow the steps below.

Step 1 - Locate the Crack

The easiest way to locate a crack in the radiator is to let the engine run until the temperature is normal high. It will take at least half an hour before pressure builds up. Shut off the engine so that the pressure forces out the coolant from the crack. Mark the cracked area with a marker or tape. Then wait for the tank to cool down and take the cap off.

Check if the crack is above or below the coolant level. If it is situated below, you have to drain some coolant until the crack shows up above the coolant level. You may remove the lower hose clamp or use a drain tank cylinder to drain the radiator tank. Make sure that you have new coolant to add once you finished repairing the crack.

Step 2 - Prepare the Crack Area for Repair

The next thing you need to do is to clean the crack with a toothbrush and dry the area. Pour a little acetone over the toothbrush and begin to scrub the crack and its surroundings. Continue scrubbing until the area is dry and no moisture reappears on the surface once the acetone dissipates.

Use the hairdryer to finishing drying the area, holding it close to the crack. Moisture will resurface again, and you will have to keep blowing over the crack until the place is completely dry. Scrub and dry the area one more time.

Step 3 - Proceed With Actual Repair

Press the tip of the soldering iron against the tie until it begins to melt, working as a sealant. Press the tie so that it wraps into the crack. Then, slowly move along the cracked area, ensuring it melts well enough to seal the crack. Keep melting at one place until the tie and its adjacent areas turn into a hot liquid.

Continue until you have melted the entire crack, wait for the liquid to harden. Cut off all unused portions of the tie. Now, you may fill the radiator with coolant and complete a test to make sure that the crack is properly sealed.

As you can see, all it takes is your new found knowledge and a little elbow grease to fix your cracked plastic radiator yourself. Now you can use your big savings for your next DIY project!