Hi Scotty, when I bought my car (2011 Corolla CE), there wasn't any coolant in the coolant reservoir. It was also low on oil. Immediately after buying it, I refilled the coolant reservoir to the max…

imjvqcel

Hi Scotty, when I bought my car (2011 Corolla CE), there wasn't any coolant in the coolant reservoir. It was also low on oil. Immediately after buying it, I refilled the coolant reservoir to the max level line and topped up the oil. Couple days later, the coolant level was reduced a bit. I refilled it to the max level line again and it stayed there since then.

My question is, what is going on here? AFAIK the cooling system is a sealed system. Hence, if the coolant level drops, that means that there is a leak somewhere in the system. However, after the second time I have filled the coolant reservoir, the coolant level didn't drop again. So what might be the case here? Do I have a leak or not? If not, then why wasn't there any coolant in the reservoir when I bought it? (it's not like the previous owner would manually remove the coolant from the reservoir). If yes, then how does the coolant level stays constant now?

Could it be that the car used to overheat (since it was low on oil and coolant), the overheating cause the coolant to expand and the expanded coolant would overflow from the coolant reservoir? If this could be the case, could this cause the coolant to leak so much that only a drop of coolant would remain on the bottom of the coolant reservoir (which was the state coolant reservoir was in when I bought the car)? If not, what might can it be?