I have a Toyota Corona and notice that my reservoir is always empty after using the car. I check for leaks and notice that there is substantial coolant in the radiator to use the car, that the operationg temperature don't climb at all.
What is worrying is the fact that the radiator is always half full as a result of some problem. So far there is no leak coming from the water pump or raditor hoses, so i check the radiator cover and notice some rust. I once change a cover on my dad's car with a similiar problem and that was the end of the problem. I will take the car to the shop to have it checked out, but i'm curious to hear your expert hypothesis.
I would like your expert advice as to what you think the problem is.