With engine cold and off, remove heater hose from firewall and make sure it has coolant inside.
When refilling cooling system you should remove 1 heater hose to allow air out of that section of the system.
If air is left in there it can cause an "air dam", water pump can't push it out.
Rangers had two different types of vacuum valves on the heater hoses over the years, when AC is off there is no vacuum, coolant is flowing into cab, when AC is on then vacuum is on CLOSING the coolant flow into the cab, so no heat.
And then the opposite, vacuum is present when heat is on and no vacuum when heat is off.
Last edited by RonD; 01-22-2016 at 10:17 AM.