How to Fix Antifreeze Leaks

Antifreeze, or coolant, leaks are hazardous to your engine's health, causing it to overheat, or worse, if not caught quick enough. Antifreeze leaks primarily come from the radiator or worn-out hoses. Use a radiator sealant to plug a small leak in your radiator. New hoses are a sure fix for a leaky hose and may be replaced quickly with common hand tools.

Things You'll Need

  • Screwdriver to match clamps
  • Pliers
  • Radiator sealant

Leaky Hose

  • Allow the engine to cool for at least 30 minutes. Wait until you cannot feel heat coming off the radiator, hoses or coolant reservoir when you place your hand near them.

  • Measure the length of the leaky hose and purchase a replacement, which automotive supply stores sell by the foot. If you do not know the diameter of the hose, bring it with you to the auto supply store to make sure you buy the proper replacement size. Get replacement clamps if the originals are rusty or corroded.

  • Remove the clamps holding the hose in place. If the clamp tightens with the turn of a screw, use a screwdriver to turn the screw counterclockwise until it loosens. If the clamp is a metal band with two tabs sticking out if it, use a pair of pliers to squeeze the tabs together and work the clamp off the hose.

  • Remove the hose from its housings. You may have to twist or apply some force to remove it.

  • String the hose clamps around the replacement hose and attach it to the housings. You may have to apply some force to get the hose all the way on to the attachment.

  • Slide the hose clamps down to the housings and secure them. If they are screw clamps, tighten the clamps until they bite into the hose but do not cut it. If they are tab clamps, squeeze the tabs together with a pair of pliers, slide them to the housing, and release the tabs. Tab clamps are designed to apply the proper amount of pressure.

Leaky Radiator

  • Purchase radiator sealant from an automotive supply store.

  • Allow the engine to cool until you cannot feel heat coming off the radiator when you place your hand near it.

  • Remove the radiator cap. Take care that you open the radiator, which is at the very front of the engine compartment, and not the coolant reservoir which is where you normally add coolant.

  • Pour the sealant into the radiator and top off the radiator according to your car manufacturer's recommended levels.

  • Run the engine for 15 minutes, then refill the radiator and coolant reservoir to the recommended levels after the engine has cooled. Allow the car to sit at least 12 hours.