Automotive

Heater core clogged shortly after flush

  • Last Updated:
  • Feb 18th, 2019 1:52 pm
[OP]
Newbie
Aug 1, 2016
97 posts
22 upvotes

Heater core clogged shortly after flush

I recently have no heat in my 06 equinox in the middle of winter. One of the two heater core hoses is hot and the other one is ice cold. I disconnected heater hoses and flushed it really well (Flushed both ways) with garden hose from a water faucet indoor and got the heat back.

This morning the air blowed cold again, one heater core hose is hot and the other one is very little warm. I rev engine a few times and heard the water squeeze sound under the dash and finally the heat came back itself.

Cooling system flushed last summer, new thermostat. Could it be a weak water pump? Why is heater core keep clogging?
Last edited by titeo1106 on Apr 10th, 2019 11:22 pm, edited 1 time in total.
29 replies
Deal Expert
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Feb 11, 2007
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Maybe you have air in the system. Make sure you do the proper procedure to bleed the coolant system of air.
If the women don't find you handsome, they should at least find you handy.
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Oct 13, 2007
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titeo1106 wrote: I recently have no heat in my 06 equinox in the middle of winter. One of the two heater core hoses is hot and the other one is ice cold. I disconnected heater hoses and flushed it really well (Flushed both ways) with garden hose from a water faucet indoor and got the heat back.

This morning the air blowed cold again, one heater core hose is hot and the other one is very little warm. I rev engine a few times and heard the water squeeze sound under the dash and finally the heat came back itself.

Cooling system flushed last summer, new thermostat. Could it be a weak water pump? Why is heater core keep clogging?
You need a reverse flush.
Deal Guru
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Mar 13, 2004
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Its possible there was still water in the system and it froze, I would suggest you make sure all the water is out of the heater core. You may need to do a proper coolant flush so you can get the proper mix of Distilled water + Coolant as you may have to much water now which is why it froze.
[OP]
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Aug 1, 2016
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Yes i did flush forward and reverse
How do I burp all the air out?
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Aug 22, 2011
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titeo1106 wrote: Yes i did flush forward and reverse
How do I burp all the air out?
Old video, but may be applicable to your vehicle.

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Nov 15, 2009
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Here's another video, two people at car would be better. If you don't have funnel.

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Read up on Heater Blend Door, it MIGHT be broken. (Plastic plate that controls the air and heat is defective) (Plastic vs Metal arm that open a door that allow the cold air and hot air though needed to be replaced).

Actuator and Temp. door(Blend Door) $100 Diagnose $1,200 parts and labor according to what I read. They have to take apart the dashboard to get to the parts. I am not to sure about the actuator but blend door is common.

I think blend door is about $30- $50 dollar. Part is cheap but labor is expensive.
[OP]
Newbie
Aug 1, 2016
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For sure not blend door because I drill hole in and manually close the blend door with a metal clothes hanger. And yes, my blend door probably broken (90% sure). I'll might keep it this way, sacrify ac for heat since I live in AB
Last edited by titeo1106 on Feb 14th, 2019 7:35 pm, edited 1 time in total.
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Aug 22, 2011
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titeo1106 wrote: For sure not blend door because I drill hole in and manually close the blend door with a metal clothes hanger
That's how you DIY and save money!
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Keep a close eye on coolant color and white smoke from the tailpipe. I am reading blown head gasket and maybe intake gasket.

Rear head gasket and number 1 cylinder had failed.

Cost about $2,800 approx.

Read up on it.

Next question will be what are the symptom of blown head gasket?

Make sure radiator fan is coming on regular interval, time it.

Water pump op mentioned is a good one too. Put a cardboard underneath to see if it's dripping.
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The other parts op may want to read up on is heater control valve.
https://www.autoblog.com/2016/01/08/sym ... rol-valve/

ECT engine coolant temperature sensor, if its defective might cause rad. fan to come to be active at inappropriate time. I think this would cause one of the cluster light to go on.

off top of my head.
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Mar 23, 2004
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MasterMK wrote: The other parts op may want to read up on is heater control valve.
https://www.autoblog.com/2016/01/08/sym ... rol-valve/
Pretty sure this car will not have a valve controlling flow to the core. Most GMs (at least back then) did not. Temperature is merely controlled by the temp door(s) and coolant always flows through the core. In the Equinox with the LNJ motor (the Chinese 3400) I'm quite certain there would be no such valve because no other 3100/3400-based car I can think of had anything like that. The LY7-equipped car I'm not 100% sure but it just seems unlikely as it's just not something GM employed as it really isn't necessary.

I would probably just replace the heater core in this case. I'd also flush all the coolant not using tap water and instead using DI or distilled water instead. Drain out and refill with a proper 50/50 of Dex and DI or distilled water. I mean it sounds like the car has some pretty ghetto fixes going on as it is so doubful OP will bother but tap water is never too good an idea in a cooling system.
[OP]
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Aug 1, 2016
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There is no heater control valve on this car. I think air in the system. The heater core was drained after flush and I put back the hoses, didn't fill it with coolant
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This is basically off internet, make sure rad. fan is working properly and timely manner, it can become defective. One person was having difficulty getting new rad. fan because they have changed the size.

There could be hair line leak in head gasket, an owner used leak sealant to stop leak $20 or so. It did remove his problem but personally I don't like it.

If op replaces heater it could be $1,100 but I don't know if this will solve his problem.

Maybe try new dealer TSTAT? sometime new tstat could be defective.

The vehicle in question is prone to overheating, head gasket failure and heater blend door failure. So the op must check coolant condition as well as oil from the dipstick to see discoloration milky on weekly basis. I was reading coolant can become quite dirty.
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titeo1106 wrote: For sure not blend door because I drill hole in and manually close the blend door with a metal clothes hanger. And yes, my blend door probably broken (90% sure). I'll might keep it this way, sacrify ac for heat since I live in AB
I don't know much about Equinox, just familiar with Civic and Sentra.

The Heater Blend Door is being manually closed with metal clothes hanger. I mentioned Actuator from my reading web, had no idea how actuator works.
Further reading tells me the Actuator right behind the glove box. It regulates amount of heat the heater puts out. This might be the problem with heater.

The op was saying, after the flush heater was working then the next day it stopped and I think work again.
When the flush was done, did op run the Equinox and check if both hose entering the firewall (into the dashboard) to the heater core, were they hot or just warm or cool. Both hose need to be hot if everything under the hood is working properly.

I was reading about Impala, in order to purge the air out. the rad. house needed to squeezed several time. I think it was both hose.
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titeo1106 wrote: I recently have no heat in my 06 equinox in the middle of winter. One of the two heater core hoses is hot and the other one is ice cold. I disconnected heater hoses and flushed it really well (Flushed both ways) with garden hose from a water faucet indoor and got the heat back.

This morning the air blowed cold again, one heater core hose is hot and the other one is very little warm. I rev engine a few times and heard the water squeeze sound under the dash and finally the heat came back itself.

Cooling system flushed last summer, new thermostat. Could it be a weak water pump? Why is heater core keep clogging?
I assume the inlet hose at the firewall is hot and the outlet hose is warm. Leading us to believe that heater core is clogged still after the flush. Is there some kind of solution liquid that can be injected in heater core to give it a thorough cleaning. If the heater core is clean the other possible obstacle would be debris dirt on outer casing fins of heater core.

I was reading one of the owner of Equinox replaced heater core. He got heat for 2 years or so, then again heater core got clogged. So what is the solution?

One of the GM Tech (not sure) on forum mentioned replacing Dex coolant with regular coolant, I assume this is the green one. I not sure this is possible ask your GM Dealer Mechanic. They were talking about head gasket and intake gasket rapidly leaking over time. The GM Tech was saying something like, it would delay intake gasket breaking down with leak. Nothing about head gasket?
Someone on forum mentioned that Dex coolant with head gasket is a deadly combination causing leak. (Not sure)

I was reading Dex coolant can get dirty like melted chocolate (I never seen it), plus the heater core being clogged. Would changing to green coolant help out?

On youtube video, a guy used compressed air to flush out heater core. After that he used some king of solution, I think it was CLR, let it sit in heater core for few minute then cleared it out. I do not know, how safe this is?
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MasterMK wrote: ...........
U post alot of info where I don't think any of it is helping. It's mostly copy and paste useless stuff no offense. Your probably consuming the OP more than anything

And OP. Why not just change the heater core
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ES_Revenge wrote: I would probably just replace the heater core in this case. I'd also flush all the coolant not using tap water and instead using DI or distilled water instead. Drain out and refill with a proper 50/50 of Dex and DI or distilled water. I mean it sounds like the car has some pretty ghetto fixes going on as it is so doubful OP will bother but tap water is never too good an idea in a cooling system.
Good suggestion!
[OP]
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Aug 1, 2016
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tmkf_patryk wrote: U post alot of info where I don't think any of it is helping. It's mostly copy and paste useless stuff no offense. Your probably consuming the OP more than anything

And OP. Why not just change the heater core
In order to replace heater core on this vehicle, entire dash needs to be ripped out which cost $1000 labor. I'm not willing to do it on 13 year old american vehicle.

What's a good procedure for bleeding all air in the system?

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