Excite Autos
Autos Home Buy/Sell Research Insurance Car Care

Learn2 Flush a Car Radiator
(11 steps)

Keep your cool

Most people ensure that their vehicles have clean oil and good brakes. Not many folks ever think about the cooling system, at least not until something goes wrong with it. And what can go wrong? Plenty: a car engine generates enough heat to destroy itself. The cooling system protects against damage, keeping the engine operating within the correct temperature range. The radiator is a major part of that cooling system, and it needs a flushing (a deep internal cleaning) at least once every two years.

Why flush? Flushing removes rust and sludge in the radiator, and cleans blocked water channels which cause overheating. But is it hard to flush a radiator? you ask. No way! It's much easier than writing a check to the local garage for repairs you might have avoided. It's also much easier than sitting at the side of the road watching steam rise from under the car hood and feeling a bit hot under the collar yourself.

Note: this 2torial supplies instructions for a simple radiator flush, not a flushing of the whole cooling system (which is a more involved project).

Before you begin

Take a minute and reflect on the scope of this project, so that you work through it efficiently and without surprises or interruptions.

  • Review the equipment you need. Make sure you have it all, including a few things you might need like a screwdriver or two, or a wrench for a stubborn clamp. You're probably familiar with this version of Murphy's Law: if you're prepared for something to go wrong, it probaby won't.
  • Gather all of the things you'll need to do this job before you start tinkering with the engine, and be prepared to stay with your job until it's completed. You don't want to be rummaging around for tools or supplies once you've begun.
  • You'll be working with antifreeze (ethylene glycol), a substance that's toxic to the most inquisitive creatures on this planet: children and animals. Make sure you follow all precautions suggested in this 2torial about handling and storing antifreeze, and dealing with spills.
  • Be sure the engine is cold! A hot engine means hot coolant under extreme pressure in the radiator. The radiator's function is to force coolant through the vehicle's engine, absorbing the high temperatures produced there. If you remove the cap before the pressure has a chance to decrease, you might be as the coolant erupts from the radiator.
   Go to Step 1 of 11

 Click here to email this page to a friend  

Step 1: Clean the radiator front and fan
Step 2: Place the drain pan
Step 3: Remove the radiator pressure cap
Step 4: Inspect the radiator pressure cap
Step 5: Inspect the clamps and the hoses
Step 6: Drain the radiator
Step 7: Rinse the radiator
Step 8: Add the coolant mixture
Step 9: Bleed the system
Step 10: Replace the radiator pressure cap
Step 11: Clean up

  • 1-2 gallons (4-8 liters) of antifreeze
  • 1-2 gallons (4-8 liters) of distilled water (make sure it's distilled)
  • (The amounts of these fluids depend on the type of vehicle, and the size of the engine and the radiator)
  • A drain pan or pail
  • A garden hose with a nozzle and a water supply
  • A pair of waterproof work gloves
  • A soft nylon brush
  • A bucket of soapy water
  • A pair of safety goggles or safety glasses
  • Proper disposal containers (non-beverage containers that are clearly labeled and can seal tightly)
  • Three or four rags (old undershirts and underwear work great)


Save Gas While Behind the Wheel
Remove Sap from Your Car
Change Your Car's Air Filter
Pump Your Own Gas
 More Learnlets...