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Old 10-02-2012, 10:08 AM   #1
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Join Date: Sep 2012
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Location: Columbus Ohio, OH
What I Drive: 2001 Sand color Ford Focus ZTS

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No Heat After Coolant Flush

There is No Heat after Coolant Flush
I read a number of threads for a few hours in this forum. It was very informative.
My 2001 Focus with 105,000 is in good condition but needs serious maintenance.
The engine is smooth and heater was working fine but coolant was rusty and medium brown in color. It definitely needed fresh coolant.
After removing the thermostat and the radiator plug, I flushed the cooling system with a water hose for at least half hour. Put the thermostat back on and idled the car for an hour. The temperature was in the normal range but there was no heat coming out. I thought the thermostat may be defective and ordered a new Motocraft thermostat from
The next day, I repeated the process with Peak Flush solvent and distilled water. Drained the Peak Flush and run the hose for at least half hour. Put it back together without the thermostat this time. Run the car for an hour and, again, the coolant reached normal temperature without overheating but there was still no heat. So, I concluded that the old thermostat was fine but needed replacement. The new one arrives in a few days.
This morning, I run a pressure tester. Hooked it to the radiator cap and pump the system to 15 PSI. I have noticed a gradual drop in pressure and a small leak below the air filter housing. I will check the hoses later on today and repair the leak. Hope that after fixing this small leak, the cooling system can hold pressure.

But still my issue remains the same: There is no Heat. Blower is working and the cable is not broken. Based on what I read, here is a list of suggestions:

1. Plugged Heater Core. Very possible considering how dirty the coolant was originally. Possibly I pushed the crop into the heater core when flushing it with the hose. I am thinking of repeating the process by connecting the the water hose directly into the inlet heater core hose and flush out the heater core. If it plugged, the heater core should not circulate the water. Is there a write up on how to properly accomplish it besides hooking a garden hose to the inlet heater core hose?
2. Water pump failure. I doubt it because the car does not overheat even after idling for an hour, but it is a possibility. However, I donít feel the water flow on the radiator hose but I am not a mechanic and may not have a good feel of the pressure flow.
3. Bad radiator cap. Very possible but it should not affect Heat Flow that much. I will buy a replacement cap though.
4. Head gasket. I can see condensation in the exhaust but it is not coolant. The exhaust drips water but other Focus seem to leak water on a cool day. Yesterday night, I can see a little pool of water on the ground under the exhaust tip. My Nissan truck had a small head gasket leak and it was blowing huge white clouds at start up. I like to believe that this is my last resort since the engine runs smooth and no presence of milky oil in the engine.
Suggestions are welcome and appreciated.

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