Owning a Car: What Newbies Need to Know

How To Flush The Radiator Of A Semi Truck

by Avery Ellis

Regular flushing of your radiator on your semi truck helps keeps your vehicle running well and extends the life of the engine. Radiators that aren't flushed can become loaded with corrosives and contaminants that can damage the engine, heater core, and head gaskets. You should flush your radiator about every six months - depending on how much you use your vehicle (check your owner's manual to see what the manufacturer recommends). Here is how you can flush the radiator on your own.

What You Will Need:

  • New Coolant
  • Catch Basin
  • Garden Hose
  • Hose Clamp Remover Tool
  • Pliers
  • Allen Wrench Set

Allow Engine to Cool

Do not work on the radiator or any of its parts unless the engine is cool and there is no danger that you will scald yourself with hot coolant.

Open Radiator Drain

The radiator drain valve is typically located on the driver's side of the truck. Place your catch basin under the drain hose (make sure the basin is big enough to collect to coolant and the water you'll be using to flush out the radiator). Open the drain valve and wait until the coolant starts to sputter out. You will then open the radiator cap and the rear block drain (you'll need a 5/16 Allen wrench on most vehicles to open the block drain) to help remove the remaining coolant.

Flushing the Radiator

Remove the return hose line from the engine block to the radiator. Take a regular garden hose and attach it to the end of the return hose. Turn the water on to start flushing the radiator out. You'll want to make sure that enough water is applied to adequately flush out your over-flow tank as well.

Add Coolant

Close the drain and reconnect the engine hose before you fill the radiator with new coolant. Check your service manual for the appropriate coolant to use for your vehicle.

Checking Your Work

Turn the truck on and place the heating switch on high until you feel heat coming out of the vents. Shut off the heater and allow the truck to run until the thermostat opens. Let it run for a while to make sure the truck doesn't overheat.

Radiators have to be maintained to ensure your truck runs well. If you feel this is something that you don't want to do yourself, take the truck to a service center that specializes in semi truck radiators to have them flush out the radiator for you.