Can the coolant still be used if it turns rusty?

[OEden]

Coolant that has turned rusty can still be used. The reason the coolant turns rusty is that high-quality antifreeze contains a certain amount of rust inhibitor and remover. When combined with the penetrating properties of ethylene glycol, a reaction occurs, resulting in the removal of rust deposits within the cooling system. Although the rusty color of the coolant does not affect the car, if the rust deposits are severe, it is recommended to drain the old antifreeze, clean the system thoroughly, and then add new antifreeze. This ensures better cooling performance. When refilling the coolant, it's important to note that the antifreeze reservoir usually has a max (maximum) and min (minimum) level mark. The coolant should be filled to a level between these two marks. Additionally, different types of coolant should not be mixed. Mixing antifreeze with different chemical compositions can disrupt their chemical balance, leading to a lower boiling point and increased corrosiveness of the coolant.