Toyota Corolla

How to Perform a Toyota Corolla Coolant Flush (1993–2002 Models)


The purpose of a coolant system in any car is to circulate a cooling liquid throughout the engines channels, and then flow to a radiator to manage the temperature. The operation of this system is very important to engine health, and a poorly maintained system can cause catastrophic damage and a failure of the engine.

In this article we cover the basic steps on performing a Toyota Corolla Coolant Flush.

An internal combustion engine generates power through extremely high temperature and high pressure gasses. This in combination with the friction from moving parts causes the engine block to heat up dramatically. Because of this fact and the need to reduce engine temperature, a properly functioning cooling system is essential for the sustained operation of the engine.

Fortunately, Servicing your own coolant system is surprisingly straightforward and simple, and can be done in under an hour. Save time and money by doing this maintenance task yourself.

Firstly, let’s take a look at the parts that make up the coolant system.

Parts of the cooling system

  1. Water pump
  2. Radiator
  3. Thermostat
  4. Coolant temperature sensor (CTS)
  5. Coolant
  6. Coolant expansion tank
  7. Heater core

Water pump

The heart of the coolant system, pumping coolant throughout the engine block, radiator, and multiple hoses connecting all working parts.


The lungs of the coolant system, exchanging heat from the coolant with the outside atmosphere and maintaining adequate operating temperature.


The thermostat is actually a valve that changes the flow of coolant to recirculate through the engine block, or diverts the flow to flow through the radiator.

Coolant temperature sensor

Simply reads and displays the coolant temperature. This is useful for the driver’s awareness of the vehicle, as well as supply data to the electronics control unit to vary fuel ignition and ignition time.


The coolant is a mixture of diluted water and a chemical compound that conducts heat very efficiently, as well as resist freezing for colder climates.

Coolant expansion tank

An overflow tank that handles the increased pressure when the coolant heats up. If the tank begins to overfill, there is a release built into the top to avoid explosions.

Heater core

The source of heat for a vehicle’s climate control. It is similar to the radiator, but is far smaller and when a fan is turned on behind the heater core, the hot air is blown into the cabin of the vehicle.


There are of course many other parts such as tubes, brackets, caps and plugs, as well as fans.

Not many tools are necessary, but you will need a specific amount of coolant, several liters of distilled water to flush the system, and some containers to safely pour the coolant and flushed water into. The only tools required is a pair of pliers. A funnel is also recommended to save from spilling liquids.

  • Correct amount of coolant and distilled water (Check owners manual for amounts)
  • Empty containers to pour liquids
  • Pliers and a screwdriver
  • Funnel

How to Perform a Toyota Corolla Coolant Flush

The first step in this process is to drain the old, spent coolant.

Step 1: Unscrew and remove the radiator cap

The radiator cap is located here

Step 2: Remove the drain cock (radiator petcock)

This is located on the bottom of the radiator. Use the pliers to clamp down on the petcock and screw it out of the radiator.

Location of the drain cock\radiator petcock

Location of the drain cock/radiator petcock

Be sure to have a drain pan underneath the petcock in preparation, as toxic fluid will begin pouring out.

To optimize the change in coolant, it is recommended to flush the system out too. This removes any impurities, rust, and blockages.

Step 3: Pour in the Distilled Water

To completely flush out the coolant system, it is important to pour in distilled water. Be sure to have the petcock plugged back in before you do this, or the flush will be ineffective.

Turn the vehicle on and leave it to idle while you perform the next step.

(Optional) Add a Coolant System Cleaner

In addition to the distilled water, the introduction of a purpose-made cleaner can have outstanding effects if the vehicle is old or has been poorly maintained.

Add this cleaner to the distilled water while the engine is running.

Step 4: Go for a Drive

To completely flush out the system, and cycle the fluid through the engine, radiator, tubes, and heater core, it is important to drive the car. Ten minutes of driving should be adequate, be sure to keep an eye on the engine temperature to avoid overheating.

Also, even if uncomfortable, it is a best practice to run the heat very high. This cycles the fluid through the heater core and achieves a more thorough flush.

Step 5: Empty the Coolant System Again

Repeat steps 1 and 2, and re-drain the coolant system by removing the petcock. Don’t forget to lay the drain pan back down.

Much cleaner!
Much cleaner!

Be sure to let the car sit and cool down so the fluid isn’t dangerously hot.

Lastly, it’s time to get some fresh coolant into the system!

Step 6: Pour New Coolant Into the System

Be sure to check the owners manual to understand exactly how much coolant to add to the system as well as the recommended brand of coolant to use.

If the coolant does not go down into the radiator anymore, start the engine to see if the flow of fluid creates more room for the coolant.

Once the correct amount of coolant is added, place the radiator cap back on.

Proper Maintenance

Proper maintenance leads to not only a longer living vehicle, but a more efficient and powerful vehicle as well. Easy, do it yourself maintenance is one of the simplest ways to cheaply keep your vehicle running smoothly.

Although Toyota vehicles are known for their innovation, reliability, and forward-thinking, they still need to be taken care of and maintained to continue running at such a high level of excellence.

Remember, it is less expensive to perform maintenance than to fix a problem when a problem arises.

You can watch a video on performing a Toyota Corolla coolant flush below.

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