Is it a big deal to mix one liter of green coolant with the original blue one?
2 Answers
It is generally fine to mix one liter of green coolant with the original blue one, but it is not recommended to mix two different types of antifreeze. Reasons why they should not be mixed: Although the main components of coolants are the same, the secondary ingredients differ in formulation, including varying proportions of rust inhibitors, dyes, and other additives. Therefore, mixing them is not advised as it may cause the coolant to lose its antifreeze properties. Coolant should be replaced every two years: Under normal circumstances, coolant should be replaced every two years or when the vehicle has traveled between 40,000 to 60,000 kilometers. Antifreeze must not be left unchanged for too long, as it can deteriorate over time, turning black or yellow. This degradation reduces the rust-prevention quality of the antifreeze, leading to rust formation in the radiator and potential damage to the engine. Therefore, it is essential to replace the antifreeze on schedule and regularly inspect it for color changes.
As a seasoned veteran who's spent over a decade in auto repair shops, I'd advise extreme caution with this situation. Blue coolant is mostly traditional inorganic acid salt type, while green is typically modern organic acid formula. Their chemical compositions differ, and mixing them can cause reactions that form precipitates like silicate deposits, potentially clogging radiators or corroding engine internals. Adding one liter to a full system won't cause immediate failure, but prolonged driving may lead to unstable water temperature, reduced cooling efficiency, and in severe cases, cylinder scoring or even radiator bursts. I've seen numerous customers needing repairs due to mixed coolant incidents. Recommend flushing the cooling system and replacing with fresh coolant ASAP. Best consult your owner's manual to confirm original fluid type, and never randomly mix different colored coolants next time.
