Can Antifreeze Be Mixed?
2 Answers
Antifreeze should not be mixed, as the original solution is a high-concentration ethylene glycol-based antifreeze, and its freezing point varies with the concentration of ethylene glycol in the aqueous solution. The method for adding antifreeze is as follows: 1. Unscrew the radiator cap, open the radiator drain valve, and drain the antifreeze; 2. Insert a rubber tube into the radiator filler port and flush the engine cooling system with tap water; 3. After draining the water from the cooling system, close the radiator drain valve; 4. Unscrew the reservoir cap and add antifreeze until the liquid level reaches the MAX mark; 5. Tighten the reservoir cap; 6. Start the engine and let it idle for 2 to 3 minutes, then unscrew the radiator cap to allow the cooling system to expel some air. The antifreeze level will drop, and you should then top it up to the MAX mark again.
I've been driving for over 20 years, and you definitely can't mix different antifreeze types - it's no trivial matter. I remember once my neighbor tried to save money by mixing old green brand-name antifreeze with newly purchased red antifreeze. Within days, his car's cooling system developed issues - sediment buildup clogged the pipes and the engine nearly overheated to destruction. Turns out different antifreeze types (like ethylene glycol-based and organic acid-based) have incompatible chemical compositions. Their reaction corrodes metal components and forms gel-like substances that drastically reduce cooling efficiency. Now I strictly follow the manual, using only matching colors - if it's green, stay with green throughout. Never experiment randomly. In emergency shortages, you can temporarily top up with distilled water, but must replace it completely soon after. Best practice is annual replacement or checking fluid level/clarity before long trips. Never skimp on this - repairs cost far more. Developing this habit protects your engine, ensuring worry-free and safe operation.