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Of all the times... No heat

JimMadsen

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So I should flush the core and the radiator at the same time. Looks easy enough. Just one minor problem. Wife got into a minor fender bender (literally, just bent pass side bumper from fog light out) cracking the bumper. Adjuster is going to check it next week sometime so I do not want to touch anything until they are done.
 


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96eb96

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To flush the heater core disconnect the heater hoses where they connect to the engine (Don't try disconnecting them at the heater core. the metal is very thin and can be damaged very easy and you will have to replace it.) Hook up a gargen hose to the heater hose that flows out of the core. Put the other hose into a bucket and have a buddy turn on the hose full blast till the water flows into the bucket. Just make sure you tell your friend to cut the water when the bucket gets 3/4 full or you'll get water everywhere. Dump the bucket and repeat till the water comes out clear. When your done try not to let any of the water spill out of the hoses, if done right you'll be able to keep the air out of the core. Reconnect everything and refill the system with full strenth coolant to offset the pure water from the garden hose. Run till hot and check for heat.

P.S. Either remove the heater control valve or make sure it's open when flushing or nothing will come out.


This is good advice but the full blast thing bothers me. You could have 80psi out of a water supply. If the core is weak, you will probably be replacing it soon. I would say 1/2 blast to be safe!
 




joe doe

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surprised nobody has mentioned the heater control exchange door...
try turning the heat/cold.knob on the dash from cold to warm and listen carefully by the heater box and see if you can hear it moving .
this door can get stuck or break leaving you stuck with whatever position it was in when it broke .
i have repaired one before .if in fact you have heated coolant coming in and out of the core(verified by both hoses being hot)i would say the exchange door is stuck .
 




mcgufer

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This is good advice but the full blast thing bothers me. You could have 80psi out of a water supply. If the core is weak, you will probably be replacing it soon. I would say 1/2 blast to be safe!

Full blast without a nozzle on the hose should not be to strong to do any damage but you are right, full blast can sometimes be to powerful. Go half power at first to be safe.
 




mcgufer

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surprised nobody has mentioned the heater control exchange door...
try turning the heat/cold.knob on the dash from cold to warm and listen carefully by the heater box and see if you can hear it moving .
this door can get stuck or break leaving you stuck with whatever position it was in when it broke .
i have repaired one before .if in fact you have heated coolant coming in and out of the core(verified by both hoses being hot)i would say the exchange door is stuck .

He said he heard the blend door moving when turning the knob. Could be that the blend door motor is moving but the door is broken in the housing. If thats the case the repair is very expensive in a shop. There are ways to turn the door manually but that is not something to attempt unless you know what your doing.
 




JimMadsen

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The exchange door is behind the glove box on the right hand side with some foam on it shaped like an oval. I visually inspected it rising up and down when changed between heat and ac.

My coolant overflow was low again and I did not see any in the snow under the car. I assume some air bubbles worked their way out so I added more.

Will take it out again later and see if any improvement.

And just to verify, the heater box is the plastic box right behind the glove box?
 




mcgufer

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The exchange door is behind the glove box on the right hand side with some foam on it shaped like an oval. I visually inspected it rising up and down when changed between heat and ac.

My coolant overflow was low again and I did not see any in the snow under the car. I assume some air bubbles worked their way out so I added more.

Will take it out again later and see if any improvement.

And just to verify, the heater box is the plastic box right behind the glove box?

Yes
 




JimMadsen

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I had low coolant again so I brought it for a pressure test at $35. Figured money well spent.

Brought it to a different shop than the one that replaced the thermostat back in August. Seems that when they put everything back together with the thermostat the "ahem" nice mechanics who had nothing but the best of intentions and pay the utmost attention to their jobs, didn't tighten the *&*&$#@ hoses. What the @*$%!

Pressure test went fine after that but the coolant looked like sludge and needed a flush (something we talked about above and I said sure, go for it) and I got the thing out of there for a total of 140 bucks. That plus a a few dollars for a new radiator cap sinnce mine appeared to be leaking and all seemed better.

I now have some slight luke warm heat at max high 90 degree setting. Nothing like what I think it should be, but better than it was. So long story short, new coolant, got flushed and cleaned out the junk, hoses all tightened. Is the heat I am getting now the best I can expect, or would there be a gradual improvement? My testing was with the engine firmly halfway up on the temp gauge driving around town.
 




RomeovilleIL

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I would say you are very likely broken blend door at this point. Assuming when the engine is warm both of the heater hoses are hot and feel about the same temp. The blend door and the blend door actuator are not the same as the directional vent control (ie floor - vent - defrost). You cannot see this door without removing the dash and taking off the top door cover. However, what you can do is here:

http://www.explorerforum.com/forums/showpost.php?p=2772369&postcount=10
 




Mebob2001

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@jimmadsen

Well you can try soaking the heater core with a cleaner by taking both hoses and point them upwards and poor straight cooling system cleaner into the heater core let it soak for a few hours, and then backflush it with a garden hose just becareful the pressure you put through it. see if that helps, mabey make sure all the door move freely.
good luck!
 




JimMadsen

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I actually started a new thread about needed help before ordering parts. The flush killed my water pump. I am leaking coolant from it. So heat issues are sidelined til I get that fixed. I forgot about the interior blend door and will check into that as soon as i can. As for the cleaning, I am pretty sure the flush would have cleared it out but I can look at that when I drain the system for the pump replacement.
 




JimMadsen

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I put some radiator stop leak in this morning for the leaking water pump and drove it to work. I know that this is a bandaid at best on a gunshot wound but I am looking for something that will allow me get everything figured out and fix it all at once with the system drained. I hope to do this in a few weeks.

OK the stop leak helped, after running the engine for 30 min and about 20 miles with the temp gauge just a hair under half, I kept my coolant in the overflow tank and only a few drops on the ground after I parked it for 30 min. It also was not actively dripping like chinese water torture while running after that drive.

But I still have no heat. It is about 10 degrees F out (up to 20 for drive home!) and I only had cold air blowing. I will re-read the thread on the blend door behind the dash panel (I actually cut a access port in it back when I had ac problems which I sealed with tape so I should be able to get to it easy) but could use a quick refresher such as this position gets heat, this one gets cool in case it is not moving on its own.

When I got to work and popped the hood I turned the heat back on (didn't help at all and made my toes cold on the drive) I went around and grabbed the hoses going to the firewall for the core and they felt cold. Now would this be a core side problem, engine side problem or a operator problem because I need it on full heat for a few minutes to notice heat at the tube.

Thanks all
 




JimMadsen

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Made it home ok and did not appear to be leaking from the area of the water pump. I have the new pump and gasket in hand so that replacement will be done. I do however, want to figure the heater problem out as best as I can.

I am now seeing two problem areas with the heat.
1. Blend door will not open more than a fraction when heat is turned on. I am thinking is may be a motor problem and the current train of thought is to pry it open and replace the door and motor at the same time before I want to start using the cooling for summer.
2. Bigger concern, both heater core hoses are cold. I assume this means a blockage somewhere in the loop. I will be doing 2 things, first put a bypass on the heater core hoses and turn on the heat to see if the hoses get hot. If they do then I will flush the core as talked about above. I will have to use gravity though because most sane people around here have turned off their outside water!

After I drove home, I stuck my hand into the heater box through the hole for the blend door 5 min fix and only felt cold air. I am led to believe that there is no circulation inside the core. Although after I just had the pressure test and coolant flush, shouldn't this have been cleared then? Or could they have just not turned the heat on to circulate through the core. I am really concerned I wil have to replace the core to get the heat back and am willing to do a lot to avoid that labor cost. I have no place right now to do it myself because of the cold. I would be worried about breaking things like dashboard clips as I bumbled my way around doing it. I also have read that a clogged heater core is usually only one cold hose and a slight greasy film on the windshield. Thoughts?

Also, would a stuck open t-stat cause the above issues (not the blend door of course)? It was just replaced a couple months ago, but you never know if that part may have failed. I can always test it pretty easily and it is cheap but don't want to drain some of the coolant until I have to.
 




Mebob2001

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Does the temp gauge on the truck hit operating temp? and if it does one thing u can try doing it replace the pump, then get a vaccum sorce, you can use another car if need be with a piece of SMALL hose and hook it directly to the heater control valve this is only to rule that out, i beleave one hose should feel some heat AFTER the heater control valve, if thats all working properly lean towards a blend door.
i had a simular issue at my work a few months ago even tho i work for GM the bleed door on the drivers side was stuck cold(dual zone HVAC system) but the rest of the truck was hot, so i removed the acuator and couldnt move the door with my fingers, then i was informed by the CN employee she use to store her pens in the vent grate, we all see where this is going, i had to bring the 2006 3/4 ton down to her bare bones to get all 6 pens out, and everything from there on worked perfctly.
But the reason i brought that up is i made sure everything else was working properly before i went to this point of removing the EVER from the dash.
And dont forget theres a quick way to access that blend door, which is something ive never done looked at or tryed:p
 




JimMadsen

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Yup I agree with you that I need to check everything before going behind the dash. My research last night shows me that typically both hoses hot, all is fine. One cold one hot, usually a blockage in the heater core, both cold circulation problem.

At this point, I know I want to replace the water pump as I do not know when it was done last and I do not trust the stop leak to last all that long. The pump was cheap and I think it would look better on the engine than on my shelf. Although it makes a good paperweight. I am thinking that if the 2 outlets where the heater hoses connect are clogged from rust from the flush it may be not getting the hot coolant at a proper flow. Or the impeller may be broken. So it could very well be a clog somewhere in there. While I have the system drained I will also pull the thermostat out to see if it is stuck open. Even though the temp gauge is right where I would expect it, the part is so cheap and a stuck open t-stat would cause no heat might as well. One place I read up on it said how to test it and then said since it is out anyways, put in a new one. Should I put a new belt on since there was a fair amount of coolant leakage on it?

After that I probably will see if there is a clog in the heater core hoses itself by running water through the water pump side of the hose to disconnected firewall side. If there is flow, then no blockage there.

Once I have heat in the heater box, then I will look at the blend door.
 




pricetag2

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I don't want to hijack your thread, but I have a similar problem. I have an EB with the fancy HVAC. When very cold, and the engine temp is normal, the air coming out swings between hot and cold. If I change from floor to floor and panel or floor and defrost, it will blow hot and then start swinging. After the interior gets a little warmer, the swinging stops. It was -4, this morning going to work and it took a half hour to not see your breath.
 




JimMadsen

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Hijack away, just be wary because the TSA may not like the term.

From my exp so far and research, the problem is either engine side or passenger side. I think you have a problem passenger side and here is why. The heater core works by hot coolant circulating through via the heater core hoses that go through the fire wall. Get your heat going and grasp the hoses (should be at the top of the firewall on passenger side right next to each other, two hoses about 2 inches across) and see how they feel. The hot coolant circulates via the water pump. The thermostat is a temp controlled spring membrane that should open when the coolant temp reaches around 190*, a stuck closed t-stat will overheat the engine, a stuck open t-stat will cause cold coolant to circulate as it never gets warm.

Since you are having heat you may be having a wonky blower motor, bad control panel, blend door, couple other things.
 




pricetag2

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Update: The problem turned out to be low coolant as described earlier in this thread. Shows you should check the easy stuff first.
 




JimMadsen

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Yeah, mine kept getting low after I started leaking post-flush. But even post flush I didn't have much heat. I got a neighbor doing the pump and thermostat tonight for $125. I would do it myself, but no where to do it in this frigid cold!
 


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JimMadsen

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New water pump, new bypass hose for the pump, new tstat and flushed out the core as described above.

I now have heat. Thanks all for the help
 




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