I have a 2000 ford explorer xls and it keeps
overheating. I have changed the radiator the
thermostat and checked the oil. It is pumping the
cooling out into the reservoir tank and leaving just
air in it causing it to over heat.
It is possible that it has a bad head gasket. Take it to a shop and have it tested for a bad head gasket.
Get a radiator pressure tester from your local auto parts store. They usually rent it for free. Pump it up to about 13 PSI. If the leak is exterior you will definitely see it squirting out.