Radiator fluid...where does it go?

[detroiter]

I don't have any leaks that I know of but it seems that over long
periods of time, the coolant level in the reserve goes lower and lower.
What could be the reason for this?

[jambo101]

I don't have any leaks that I know of but it seems that over long
periods of time, the coolant level in the reserve goes lower and lower.
What could be the reason for this?
Ultimately over time evaporation will eliminate a small amount of coolant..

[thepartsmancometh]

bingo. evaporation is the biggest (non-leak or usage) culprit. if it was using it (ie: head gasket issues), you'd probably notice

[YarisSedan]

Coolant level will go up and down depending on the temperature and the time you check your level. That is the design of the radiator cap. As the coolant expands and contracts it will draw from the overflow bottle and refill it. As long as it is between the 2 lines you are fine.

[bronsin]

Its possible you have a leaky hose clamp someplace.

DONT PANIC!

These things leak in cold weather. Usually just a few drops until the engine warms up. Then it stops. You might notice a wiff of coolant in the air at startup. If you want you can start your cold enngine, put the parking brake on (on level ground please) and go look under the engine for 10 minutes for drips. If you find a leak and can trace it, a tightening of the hose clamp is in order. Sometimes the clamp needs replacing.

But this is mostly irrelevant. These minor leaks dont do any harm. But if your smelling coolant at times that might be why?