Hi Friends, so my coolant reservoir is at MIN at operating temp after some driving. Does it means I need to add more?

Should I just top it off to MAX while it is running in the reservoir?

 

Thanks.

Leave room for expansion. Your coolant system breaths as it heats up and cools down. When cold the level should be at or just above the MIN mark. When hot it should be between the MIN and MAX marks but not above the MAX. If you overfill it you will end up with coolant on the ground with you wondering where your leak is.

19 minutes ago, kickstand80 said:

Leave room for expansion. Your coolant system breaths as it heats up and cools down. When cold the level should be at or just above the MIN mark. When hot it should be between the MIN and MAX marks but not above the MAX. If you overfill it you will end up with coolant on the ground with you wondering where your leak is.

So if the coolant is at MIN while the car is running and at operating temp top off the reservoir to between min and max at least? Seems like…

15 minutes ago, MH77280Z said:

at operating temp top off the reservoir to between min and max at least? Seems like…

That's what I would do. I wouldn't do it with the engine running though. I would shut it off first.

As your engine heats up the coolant expands and some of it is released into the reservoir so if you have too much in the reservoir, it will overfill. When the engine cools off, it creates a vacuum and draws coolant back into the engine. So when the engine is HOT you should be between the two marks, usually near the MAX. After the engine cools and draws coolant back into the radiator you should be above the MIN mark. Add coolant when the engine is cold to just above the MIN mark