87 Suburban Heater Core Box Question

[Dumaine]

Hi, I have a 87 Suburban that I needed to replace the heater core (leaking). For a first timer the process actually went well thanks to Internet videos and Forums.

Question is this....inside the box there is a baffle (mixer). Is it supposed to fit snug on the rod and move when the rod moves, or is it moved in position with the airflow that crosses it depending on your settings?
I ask because when I got it all back together the rod can turn freely without any movement to the baffle (mixer). Also when I connect it to the main rod like it is supposed to be assembled, and slide the rod forward it turns the second rod but the baffle (mixer) does nothing. I can reach in the hot/cold door and move it forward or backward. I was under the impression that the rod could only slide in one way, mine can slide in in any position.

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[newbie17]

The rod has a flat spot that must engage the flat spot in the mixer. The end of the rod with the flat spot will be visible in the small "witness" hole on the main plenum.I always coat the rod with a little grease before insertion to make things easier.

 

[Dumaine]

I am going to take a guess and say that it all must be worn down. I did notice the flat spot at the end of the rod (if that is what you are referring to) but it seemed rather smooth and just slid in any way I attempted to slide it in. Not sure if it is a big issue at all since I get floor heat on the heat setting and defrost when in the defrost setting. After replacing the clip on the front door I also get great flow coming out the front where the vent ductwork attaches. Yet i still need to put all the ductwork back which was removed for another issue.

 

[chengny]

I am going to take a guess and say that it all must be worn down. I did notice the flat spot at the end of the rod (if that is what you are referring to) but it seemed rather smooth and just slid in any way I attempted to slide it in. Not sure if it is a big issue at all since I get floor heat on the heat setting and defrost when in the defrost setting. After replacing the clip on the front door I also get great flow coming out the front where the vent ductwork attaches. Yet i still need to put all the ductwork back which was removed for another issue.

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[Dumaine]

Great idea Chengny

 

[chengny]

Great idea Chengny

Things didn't look so good for a while however.

https://www.gmsquarebody.com/thread...ousing-reference-pics.4809/page-3#post-170554

 

[radio2000]

I can't seem to get the rod out so I can replace the heater core, any advice?

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[radio2000]

Got it out and managed not to break anything.

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