The radiator overflow container in your car catches excess coolant from the radiator and keeps it from spilling into the environment. A short length of hose, called a radiator overflow tube, connects the radiator to the radiator overflow container. As the pressure in the radiator rises, some of the coolant will vent automatically to keep the system at optimum pressure. This vented coolant passes through the radiator overflow tube and into the overflow container. You should repair a radiator overflow tube as soon as possible to help prevent radiator coolant from leaking into the environment.
Things You'll Need
- Tape (electrical, duct, hose repair)
- Radiator fluid
Turn off the car where you want to repair the radiator overflow tube. If you are driving, pull off to the side of the road. Set the car in park. Remove the keys from the ignition. Pop the hood. Allow the engine about 30 minutes to cool off in order to be able to work safely around it.
Locate the radiator overflow tube. These are usually black and about 3/8 inch in diameter. The hose runs from the radiator cap to the top of the overflow tank, which is typically mounted to the side of the engine compartment.
Look for the leak in the overflow tube. You should be able to see coolant where there is a hole.
Dry off the area around the hole with a rag.
Start wrapping tape about 2 inches above the hole. For this repair, you can use electrical, duct or emergency repair tape. Wrap the tape another 2 inches past the hole. Repeat your wrap, this time starting below the hole and wrapping upward in the opposite direction. Trim off excess tape with the knife.
Top off the radiator overflow tank, if needed. You should be able to see a fill line on the side of the tank where the radiator level should be. Use a 50-50 mixture of water and radiator fluid.
Tips & Warnings
- Use distilled water, if possible, when topping up your radiator.
- This repair procedure is good for temporary fixes. When possible, have the overflow tube replaced.
- Radiator coolant is harmful to animals, such as dogs and cats, who will try to drink it. Clean up any spills as soon as possible.
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