Here are some really good tips on how to change your antifreeze. A complete flush is necessary when changing colors.
Flushing the cooling system includes the following steps.
- STEP 1 Drain the system (dispose of the old coolant correctly).
- STEP 2 Fill the system with clean water and flushing/cleaning chemical.
- STEP 3 Start the engine until it reaches operating temperature with the heater on.
- STEP 4 Drain the system and fill with clean water.
- STEP 5 Repeat until drain water runs clear (any remaining flush agent will upset pH).
- STEP 6 Fill the system with 50/50 antifreeze/water mix or premixed coolant.
- STEP 7 Start the engine until it reaches operating temperature with the heater on.
- STEP 8 Adjust coolant level as needed.
Bleeding the air out of the cooling system is important because air can prevent proper operation of the heater and can cause the engine to overheat. Use a clear hose attached to the bleeder valve and the other end in a “suitable” container. This prevents coolant from getting on the engine and gives the technician a visual clue as to the color of coolant.
Check service information for specific bleeding procedures and location of the air bleeder fittings.
Here is a video I found that is very accurate and fact based