Heater hoses routing diagram needed

KENNETH DAVENPORT

MEMBER
2006 PONTIAC G6
3.5L
V6
2WD
AUTOMATIC
200,000 MILES

I was given my car recently so when looking to see why the heater wouldn’t heat I found that it had the heater hoses cut off at the firewall side. I’m guessing they just connected the two on the motor side together to bypass the heater core. Problem is I’m not sure exactly where the heater hoses should be ran and where/what each one connects to/at. Maybe a picture or a detailed diagram would be a life saver for me. Any help is greatly appreciated. Thank you

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Saturday, March 27th, 2021 AT 5:40 AM

3 Replies

STEVE W.

MECHANIC
14,081 POSTS

If the core is bypassed I would suspect it leaks. There are two molded hoses that connect the heater core to the heat transfer tubes on the engine. These are the inlet and outlet positions in order. To replace them you have to drain the coolant and then use clamp pliers to remove the hoses. What I would do before I did that would be to get a pressure test kit and block off one of the tubes and connect to the other, then apply about 15 pounds of pressure and see if the system holds that pressure. If it leaks it will slowly lose pressure.
In that case you will need to replace the heater core. That requires that the dash be removed to get the HVAC case out and apart to get to the core. I would replace both the heat and AC cores while there.

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Saturday, March 27th, 2021 AT 8:32 PM

KENNETH DAVENPORT

MEMBER
2 POSTS

Well, I was pretty sure the way I ended up hooking it up was correct and it was according to the two pics you provided. Those two pics was exactly what I needed but I took a chance on it after attaching two clear hoses to the heater core and back flushing it with water, it was surprisingly clean and I felt for any wetness in the floorboard and as far as I could feel it didn’t leak. So after just it holding water pressure for at least a hour and the floor still dry, I pulled my flush hoses off and put my new molded hoses on it, filled n bled the cooling system and turned the blower on and lucky me warm air was blowing out the vent. And so far no need for water socks yet, seems to be holding its own as well as I can tell. Of course after all this and bam I didn’t stop to think about who was maintaining the car before me then it all kind of makes sense being my daughters boyfriend (the self proclaimed gene-yus) was making the repairs when necessary. So odds are I’m sure I’ll be back soon replacing who knows what with parts actual mechanics (not self proclaimed gene-yususses) use. So I will definitely buckle up for what I’m sure at the very least, will be a bumpy ride for a lil while. Until I get thru all his masterpieces-of-$#@* “repairs” he’s made. Hopefully I make it out the other side n thanks so much for your time and knowledge and the pictures I asked for. I appreciate your help greatly.

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Sunday, March 28th, 2021 AT 4:01 AM

STEVE W.

MECHANIC
14,081 POSTS

Okay, as you have it connected up you can still pressure test it, just use a conventional radiator pressure test kit, you can find them as loaner tools in many parts stores. I suppose it may have been a bypass to "cure" a stuck blend door or someone thinking that removing the heater core from the system was a good thing. The pressure test would at least tell you if you should expect any issues.

https://www.2carpros.com/articles/radiator-pressure-test

If you opt not to do it that's okay as well, we'll be here either way.

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Sunday, March 28th, 2021 AT 10:36 AM