Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum

Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum (
-   General Technical Chat (
-   -   No Heat After Coolant Flush (

diexodos 10-02-2012 10:08 AM

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.

sailor 10-02-2012 10:31 AM

Plugged is a possibility, but I'd try to flush it out in reverse order (apply water hose to outlet) instead of trying to push things through from the inlet side as your note describes.

Air in the system is a common cause of such issues with this type of system that has a coolant tank higher than the radiator with bleed hoses to the tank from high points in the cooling system's plumbing. They are SUPPOSED to flow just enough to bleed out any air, but being quite small they are MORE likely than your heater core to be plugged.

Check out all those small plastic lines - once clear your problem may be solved!


diexodos 10-02-2012 02:08 PM

Sailor, thanks for the advice. I am new on Focus and although I worked on other cars, each car is a unique experience by itself.

I will continue to flush and test the cooling system with distilled water. Once everything tests ok, I will replace the water with use 50/50 ethylene glycol antifreeze.

I will check all hoses and replace some of them. Can you send me a link for a proper bleeding of the cooling system? During testing stages, I will not be using the thermostat. Is it necessary to follow a bleeding procedure if the thermostat is not installed?

sailor 10-02-2012 02:38 PM

A long life non-silicate coolant like the Ford Gold that came stock in mine is better for the water pump seals (for example) and it only has to be changed after 5 yrs. instead of 2 yrs. so the price evens out.

There's a lot of advice about bleeding I've seen, but none of the ones I know about have bleed screws that NEED to be dealt with like some other vehicles have. The system instead uses those tiny plastic lines to self bleed - on mine I've changed the coolant and only needed to top up at the reservoir to get it properly filled.

Some have mentioned removing an upper hose to fill it quicker, I'm afraid I haven't read a factory manual to see if that is "officially" recommended.

Someone with more knowledge of your particular engine will probably chime in with more details....


diexodos 10-03-2012 07:08 AM

A number of the hoses seem very soft and possibly disintegrated from the inside. I will replace all hoses and pressure test again. The cooling system lost only a few ounches of water in three days but it is not holding pressure because of leaks. One leak comes from the lower hose to the radiator reservoir. The rubber seems very soft and dissolves on the touch. Weird., It feels that it chemically reacted with oils and broke down. I am not sure of the thermostat housing condition unless it is a maintenance items that needs to be replaced.
The next plan is to replace hoses, flush heater core and retest pressure. If it does not hold the pressure, the radiator cap and thermostat housing will be replaced next. At that point I should be good.
Which commercial brand is free of silicates and compatible to Ford Gold? I can readily get Prestone, Peak and Zerex. Reason I shy away from dealer brands is because any needed repair in the cooling system will necessitate another trip to the dealer for coolant.

IH84DZ 10-03-2012 08:27 AM

If the hoses have become spongy and soft someone has used the wrong coolant or an additive of some sort along the way. Based on your findings (good job btw) sounds like a classic case of a plugged core or an air bubble. I vaguely recall the focus using an outlet restrictor to reduce noise through the heater core but I'm not positive this is the case. Another reason why small floaties could have plugged you up.

These don't seem to be hard to burp - my SVT has been drained several times and had a thermo housing replaced and I've never had trouble getting bubbles out... the degas bottle is the highest point in the system so it works as designed (unlike Windstars, cobra mustangs, navigators, aviators, etc) so my money is on a plugged core especially given the color/condition of it as you found.

The pressure leak will only cause you to lose coolant - it shouldn't affect the cooling ability of the engine or the heating ability unless it's literally running out.

Backflushing a foci heater core looks like a bitch but I'd say it's the only thing worth your while at this point

All gold coolants are not created equal. Just read the bottle carefully but you want coolant with nitrtite additives. Universal coolant is b.s.

diexodos 10-03-2012 01:22 PM

Back flushing the heater core and replacement of hoses is the first step. Is there a vendor that sells all hoses as a package deal? I see a total of six hoses that need to be purchased: two hoses to the heater core, an upper hose to the radiator, a lower radiator hose and two hoses to the reservoir.

When do you know that the thermostat housing needs replacement? Should I spray dish washing fluid and look for bubbles? Also, as I said on an earlier email, the thermostat is removed for now until I am done flushing it. But I have used the thermostat gasket to provide a seal and minimize leaks. Without the gasket it leaks crazy. Is it possible that the gasket by itself does not provide a good enough seal for the thermostat housing? I see on the internet the presence of two gaskets, a large one for the thermostat seal and a small round one. Where does the small round gasket connect to?

The reservoir has lots of crop in it. It is hard to clean the inside. I can see replacing it too.

Trying to keep the cooling cost restoration under a $200 budget since other maintenance areas need fixing. Any cost saving ideas, such as vendors and stuff are welcome.

diexodos 10-03-2012 03:57 PM

I made a listing of nine replacement hoses for DOHC engines:
Upper Radiator Hose - Dayco $12.71
Lower Radiator Hose - Motorcraft $25.86
Radiator to Reservoir - Gates $9.51
Reservoir to Radiator - Gates $9.34
Reservoir to thermostat - Gates $9.74
Pipe to Thermostat - Gates $9.29
Pipe to Heater Core - Gates $17.84
Heater Core to Connector - Gates $13.71
Connector to Thermostat - Gates $6.12

You can replace all hoses for $114.22

amc49 10-03-2012 07:00 PM

Or use bulk straight hose in all positions but the top and bottom main radiator hoses. I do that on both my cars.

You MUST use at least a thermostat outer plate to put gasket in there, the gasket will not stay in place without the stat outer ring to keep it in place. You also need the thickness of the stat plate to fill the gasket out to proper thickness or eventual leak from not enough preload or squeeze on the gasket. I have pulled so-called bad stat housings back from the dead simply by adding a washer to the thickness of stat/gasket to make it thicker, the stock stat cover warps in at the bolt corners to release pressure in 3 spots and leaks then. The added washer makes the pinch point thicker and then it seals where it was leaking before. One of mine now running for years like that.

The stat must have its' small edge hole facing straight up to properly bleed. It must also have the proper size and spaced length disc on the backside or the heater will NEVER get hot. The disc moves back to shut off the port, that then forces the core to heat up. I have seen crap stats in the past that were not spaced right on the disc and they would not heat up, the disc would not contact the hole to seal. When that hole is not sealed the heater loop is bypassed.

If stat in right system's bled by the time motor is hot, I NEVER bleed them longterm.

The smaller round gasket seals the housing to the head itself.

I still use old school green coolant, it lasts longer than they would have you believe.

sailor 10-04-2012 08:17 AM

Good Info on the thermostat & housing!

Main reason I like long life over green is the theory that the silicates in green can chew up water pump seals over time. To date all the pumps I've replaced were in vehicles running green (of course that's been around a lot longer...). Bought into the theory when Honda went long life for their Cycles after all the old Gold Wing water pumps started leaking....

All times are GMT -5. The time now is 10:46 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.