Is the fluctuating level of antifreeze in my car normal?

Seeing a higher level in the overflow tank when the engine is hot is normal.

Best case scenario is that the cooling system had a lot of air in it, and you are gradually replacing air with coolant as you add coolant at the overflow. (Each time the engine cools, coolant will be drawn in from the overflow to the radiator.)

It's not good that the car was low on coolant when you bought it. That might indicate an ongoing leak.

Worst case scenario is that your car has a blown head gasket or cracked block, and that your coolant is leaking into the cylinders, and going out the tailpipe.

It's not unusual for the coolant to rise and fall. Great example, if you open the radiator cap and the radiator is full, don't pay to much attention to the resevior. It is there for the use and expansion of the coolant as the car warms and cool. But as I started to say, if you open the cap when the car is cold and start it and let it warm while watching it, you will see the fluid drop as soon as the thermostat opens. When it closes, it will rise again and so on. This is normal. If you haven't sopotted any leaks, nor do you notice any white smoke from the exhaust, I wouldn't be real concerned. But if the loss is pretty major regularly, then it may be a sign of a leak or poss. head gasket going bad. Hope this helps.

I have a Hyundai Azera 2009. Have same issues with my car lately. took it to a mechanic and they fixed the water pump which was leaking the coolant from the reservoir. Best way to tell your car is leaking is to spot the puddle under your car. take a picture or put a paper to find out where it's leaking over night. If it's pure coolant, it maybe your reservoir if rusty and on the other side it maybe the radiator. Your coolant may need flushing if there is a debris blocking the hoes. Depending on the make of your vehicle prices can range from anywhere $400-2k. Head gasket is expensive to fix. Did your 'engine check' light came on? If it did, there is your problem. Take it to your dealer as soon as you can or it could cost you more. Always check your vehicle in the summer, that's when most cars experience over heating.

the way it works is that you fill the radiator clean to the top when the engine is cold, fill the reservoir to the cold mark ! after the engine gets hot it will spill out into the reservoir and after it cools down then the radiator will suck it back out of the reservoir ! as long as you don,t have any leaks, don,t have antifreeze in the oil or no white smoke blowing out the tailpipe then you have nothing to worry about ! you might try to change the thermostat if you feel it,s not working right !

Yes, this is normal. Relax. Now if it the coolant level gets steadily lower each time when checked at the SAME temperature, you have a leak in the system which will sooner or later need to be addressed. But it has to get pretty low before the car will overheat.

None of what you point out is irregular. The factories have squeezed each penny out of the radiators which of direction cool the engine so that climate could make them marginal when not relocating good. You would determine the fan operation and be certain there is not any construct up of particles choking air drift. After that, i might no longer fear an excessive amount of until it gets worse.

Fill to the MIN line when cold and keep an eye on it. Also, remove the radiator cap when cool and insure the radiator is completely full.