I have a 2000 ranger 2.5l 4cyl. Ive changed thermostat did a complete flush of the coolant and flushed the heater core 3 different times and still my heat barely works. Just blows luke warm air. Both hoses going into the heater core are scalding hot to the touch. Ive replaced the hcv as well to no avail. Im at my wits end its 0 degrees here and i havent had hardly any heat all winter. Please help.........Thanks