Replace a Leaking Radiator Hose

Replacement of a leaking radiator hose on your car is fairly easy. All you need are a few basic tools and minimal mechanical skills. You can save money on a mechanic and leave yourself with a sense of accomplishment if you learn how to replace a leaking radiator hose.

Steps

  1. Begin by identifying the leaking radiator hose that needs to be replaced. Do this by running the car to operating temperature.
    • Park the car on level ground with the engine running in park and emergency brake set.
    • With the car running, visually inspect the hoses for collapse or leaks and do the same thing with the engine off.
  2. Drain the engine coolant when it has cooled. Open the petcock on the lower end of the radiator and drain it into a bucket.
  3. Loosen the clamps on the leaking radiator hose.
  4. Grab hold of the hose and begin to work it off of the end it is attached to.
    • Remove the hose clamps from the leaking radiator hose.
    • If the hose will not slide off easily use a carpet knife to make a slice parallel to the hose from the hose end to just past the nipple it is attached to. Peel the hose from the nipple like an orange.
  5. Push the hose firmly over the stub-out from the radiator and engine seating firmly over the rib that runs around the outer section of the stub-out as far as possible.
  6. Slide the clamps down the hose to within the width of the clamp off the end of the hose and tighten as necessary.
  7. Close petcock on the bottom of radiator and begin filling of radiator with the proper mixture and type of coolant.
  8. Put the radiator cap back on and continue filling the system up at the coolant reservoir to cold level.
  9. Start the engine and allow it to come to operating temperature.
  10. Check for leaks watching the fluid level in the reservoir tank which should drop as the thermostat opens up.
  11. Drive vehicle as you would normally and check coolant levels and recheck for leaks.
  12. With the radiator cap off, allow to drain into a pan at least 2 gallon/3.8 liter in size.
  13. When you turn the engine off the back pressure should reveal any leaks not seen.
    • Top off the coolant as needed.
  14. Slide the clamps onto the new hose.



Tips

  • Clean off the stubs from the engine and radiator to remove any old pieces of hose still stuck on them before installing a new radiator hose
  • There will be a top hose running from the radiator to the engine thermostat housing (usually located at the top section of the engine above the water pump). On a rear-wheel-drive car, it will be at the front of the engine. On a front-wheel-drive car, you will find it on the right (or passenger side) of the car. The second radiator hose is located at the bottom of the engine coming off of the water pump running to the bottom of the radiator.
  • The two types of clamps are pinch type and screw type. With the pinch type, use a pair of pliers to pinch the two ears on the clamps and slide them back off of the end of the hose. On a screw type, use a flathead screwdriver to loosen the ratchet mechanism that tightens or loosens the band on the clamps.
  • Removal of equipment other than the hose may be necessary if they prevent access to the hoses. Use a digital or video camera to document what and how the equipment came off.
  • Some makes and models of automobiles may require that you bleed the entrapped air from the coolant system for it to properly cool. Check on line with your car owners' forum to see if you need to do this for your car.
  • Apply a light coating of petroleum jelly to the inside of the hose. This will aid in slipping the hose on over the stub outs.
  • If the hose has been on it for a long time, you may need to split the end of the hose with a box cutter and peel it off the end.

Warnings

  • Allow the engine to cool before draining coolant to avoid scalding.
  • Do not drain coolant onto the ground, as this is hazardous waste and needs to be disposed of properly.

Things You'll Need

  • Flathead screwdriver
  • Medium-to-large pliers
  • SAE/Metric combo wrench set
  • Ratchet socket set
  • 2 gallon (7.6 liter) pan
  • Box cutter
  • Paper towels
  • Petroleum jelly
  • Funnel
  • 1-2 gallons (3.8-7.6) liters of 50/50 coolant
  • Specific radiator hose for your car

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