Fluctuating coolant levels

im trying to understand what I see here. Vertically, half the tank is full. The other side appears empty.

then, I drive 7-8 miles it re-appears again.

I initially thought I was having a coolant leak. But it doesn’t appear so. I had been hearing lots of sloshing on ICE every time in park or while driving so I checked it. Seen it was low like this, I fill it, but this cycle keeps continuing of an appeared to be empty half of tank to not being empty.

Still not sure if this is a coolant leak.

I’ve had heat exchanger swapped before. I’m not having any type of car symptoms or heat issues.

Also, the coolant mess you see in photo 1 is from an intentional overflow. Someone was filling it and simply made it a mess. Photo 2 I wiped down during same hour.


the coolant slosh became noticeable before I even opened coolant cap once.


Vehicle at 203k miles now.

 

I want to add: the person overfilled my tank. And currently, it doesn’t appear overfilled anymore.

any recommendations to consider here? Not seeing any coolant loss, or issues with car.