8 Steps to Flush a Diesel Radiator

Hi everyone. Today I found a great article in Do It Yourself that I know many of you will enjoy reading or possibly relate to. The original article can be found here - https://www.doityourself.com/stry/how-to-flush-a-diesel-radiator - if you’d like to read the article there, or I’ve pasted parts of it here to share it. It’s well worth a read.

To keep your diesel radiator running at peak efficiency, it's important to flush and refill it on a regular basis. Many people wait until the antifreeze visually looks badly contaminated, but if you anticipate this and monitor it on a regular basis, you can keep your coolant system in peak condition. Check your vehicle's manual for suggested time periods. It is not difficult to learn how to flush a diesel radiator.One rule of caution is to always work on your radiator when it is cool. For your safely, do not work on it while it's still hot.

Step 1 – Prepare Vehicle. If at all possible, park your vehicle on a slight incline, facing downhill. It is helpful to turn the wheels facing away from the hill in order to prevent it from rolling downwards while in park. Also, put on your emergency parking brake at the same time.

Step 2 - Allow System to Cool. Allow your vehicle to completely cool down, at least one to two hours. 

Step 3 – Drain System. Place the bucket under the radiator drain and open with a pair of pliers. You may find it handy to use a 3' length of ?" tubing to direct the flow into the bucket, although this is not necessary. Open the radiator cap.

Step 4 – Refill System with Water. Once all the antifreeze has fully drained, close the radiator cap and tighten the radiator drain plug. Using distilled water, fill the system to its capacity.

Step 5 – Turn off Vehicle. Turn off the engine and allow it to cool again.

Step 6 – Repeat Steps 2 to 4. You should repeat steps 2 through 4 of draining and filling with water, then allowing the engine and heater to run, until it drains clear. How dirty your antifreeze is will determine how many times you need to repeat this procedure.

Step 7 – Refill with Antifreeze. Once the water is clear and free of debris, it's time to refill with fresh antifreeze. There is no concern if there is a little water left in the system. Be sure that the radiator plug is firmly seated. Refill the system with the amount of antifreeze that your engine's manufacturer recommends. Only dilute the antifreeze per instructions on the bottle or by the manufacturer of your vehicle. Some antifreeze requires an additive, so be mindful when you are purchasing it that you have what you need. Replace radiator cap.

Step 8 – Start Vehicle. Start your vehicle and turn your heater on its highest setting. Allow to run until it reaches its normal operating temperature. At this point, your vehicle is ready to drive. 

Check the coolant in your diesel radiator after running for a few days, to be sure that it is at its proper level and there are no leaks.

Hope you enjoyed the article. Please feel free to contact me on (0403) 243-786 or email at [email protected].

 Thanks,

Matthew