2002 Mercury Sable 6 cyl Two Wheel Drive Automatic 165000 miles
1. I researched and there is a TSB on this from Ford for the Blend Door Binding or Sticking.
2. I purchased a blend door from Ford for $6.00.
3. I looked at the blend door and all Ford did was cut a piece of the rubber seal off to prevent it from binding or sticking, so instead of breaking the air unit apart to replace the door, I cut the seal with a razor blade.
4. Still no heat after reassembly.
5. The next day I flushed the cooling system. I know, should have done this first. I measured the output of the heater at 150 degrees after the flush.
6. Replaced with fresh coolant. Heater worked fine.
7. Got in the car this morning and no heat.
I worked on the car in a shop that was heated. Is it possible that once the blend door warmed up, it worked fine, but when I let it sit overnight in 20 degree temperatures, the door is less pliable and then binds? It's either that or the blend door actuator is not working. Just want a second opinion.
This is the Check list for no heat
if you go through it, it should show when is the problem
I would assume its a heater core that need to be isolated and flushed
Check coolant level
Is the car reaching operating temp (if not or engine taking long time to reach operating temp suspect and replace thermostat )
Check heater core hoses if both are hot,
If both hoses hot and not enough heat inside suspect blend door actuator
If one hose hot and the other warm or cold the heater core need to be flushed (very common)
as a 1st step
these are the steps
WARNING: NEVER REMOVE THE PRESSURE RELIEF CAP UNDER ANY CONDITIONS WHILE THE ENGINE IS OPERATING. FAILURE TO FOLLOW THESE INSTRUCTIONS COULD RESULT IN DAMAGE TO THE COOLING SYSTEM OR ENGINE AND/OR PERSONAL INJURY. TO AVOID HAVING SCALDING HOT COOLANT OR STEAM BLOW OUT OF THE COOLING SYSTEM OR DEGAS BOTTLE, USE EXTREME CARE WHEN REMOVING THE PRESSURE RELIEF CAP FROM A HOT COOLING SYSTEM OR DEGAS BOTTLE. WAIT UNTIL THE ENGINE HAS COOLED, THEN WRAP A THICK CLOTH AROUND THE PRESSURE RELIEF CAP AND TURN IT SLOWLY UNTIL PRESSURE BEGINS TO RELEASE. STEP BACK WHILE THE PRESSURE IS RELEASED FROM THE COOLING SYSTEM. WHEN CERTAIN ALL PRESSURE HAS BEEN RELEASED, PRESS DOWN ON THE PRESSURE CAP (STILL WITH A CLOTH), TURN AND REMOVE PRESSURE RELIEF CAP.
lower the coolant level
Locate the two hoses running to the heater core
disconnect them at the engine side leaving hoses connected to heater core throw the firewall
make sure you pinch and close the bypass hose between the two heater hoses
use garden water hose and compressed air if possible
run the water and follow by air throw one side and out the other and vice versa
do that two to three times watching what leaving the heater core you are looking for the good flow and clear water to run throw
top off coolant system
let me know