Is it a big deal to mix one liter of green coolant with the original blue one?

[Athena]

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.