rent a pressure tester and maybe even get one that can test the cap too. small leaks could be like a tiny drip from the thermostat housing, loose or cracked hoses, etc.
It could be that you don't see the leak because it is evaporating as it falls out since it's likely only leaking when running. Do you notice a smell of coolant?
It could be that you don't see the leak because it is evaporating as it falls out since it's likely only leaking when running. Do you notice a smell of coolant?
