So I got an issue with my 1995 Nissan Maxima with 166.5K miles. Car runs great, doesn’t overheat and the radiator is always full of coolant. However, the reservoir loses coolant. I would fill it to the full mark, then after 2-3 weeks it would be a little bit left in the reservoir below the minimum mark.I would leave it (not refill it) and the small amount of coolant will remain in the reservoir and still not overheat. Radiator remains full as well. The radiator and both radiator hoses were replaced last summer, so I don't think those are leaking. I’m thinking either the reservoir is leaking or it’s leaking from the hose that goes from the radiator to the reservoir or leak from both. Any help is appreciated.
Have the car warm-up and look around for any leaks. It may be a very small leak considering it takes 2-3 weeks to empty out. The radiator will remain full as long as there is extra coolant in the reservoir. Have you checked your oil to see if coolant is mixing with it? Look at each coolant hose and its connection, check the water pump, check the thermostat, look at your engine block to see if any is leaking from the head, check underneath the radiator for slight leaks. The engine could even be burning small amounts of coolant if the head gasket is bad. Check everything that has to do with the coolant system. Please keep us posted.
