Front heater core removal

C-ya

Original poster
Member
Aug 24, 2012
1,098
Is it really as hard as it sounds in the manual? Is there another way - an easier way? I'm getting a coolant smell from the vents when the heat is on, so I'm guessing the front heater core is leaking a bit. The reservoir isn't getting low very quickly (I'm checking about once a week and can't really detect much change), but I'm smelling it, so it must be coming from somewhere.

Good grief! I don't want to have to discharge and recharge the A/C! Leave it to some fricking fracking knuckleheads that don't work on their own vehicles to design some $hit like this. We need an "Engineers at the home garage" day like we used to have "Engineers at Sea" days when I was on the ship. I asked one how to perform a maintenance check on my transmitter while underway in the manner in which he wrote it up. He couldn't do it and went back and changed his procedure.

Plus removing the entire dash? Really??
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Unfortunately, that's the process. As the joke goes, when they build a car, first they put the heater core on a little pedestal, then they attach every other part to it.
 

blazinlow89

Member
Jan 25, 2012
2,088
Have not looked at the procedures for the TB yet, I did have the opportunity to tear into an 01 Dakota a few weeks ago. 12 hours and the damn heater core was fine (the guy swore he had removed about a gallon of coolant off the floor). It was condensation from the AC vent tube ( which is what I told him I thought it was).
 

Mooseman

Moderator
Dec 4, 2011
25,178
Ottawa, ON
I've had to tear into my dash to replace the A/C evaporator core. Took me a whole day but it can be done. It helps to remove the center console for extra working room, which is not in the manual.
 

gmcman

Member
Dec 12, 2011
4,656
Make sure your heater hoses aren't leaking at the firewall or at the heater core side and spilling into the evaporator box.

When it gets real cold this is where old hoses tend to leak, I have seen countless drips of coolant in my day just under the firewall and all that was needed was either a new hose or have the hose trimmed slightly with fresh clamps.

Use factory clamps.

Worth checking before you gut your dash.
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
gmcman, thanks for that tip. I'll certainly be looking before I tear into anything!
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
OK, reviving an old thread. It has come to the point now that I have to do it.



I looked at the hoses yesterday - well, more like felt the hoses yesterday - and I can't see that I have enough room (V8) to get to them to get them off without knowing "the trick". I found the drain, thinking all the fluid was draining out the front, but it was dry. I pulled it off, stuck my finger in the hole (!) and even stuck the little downspout (stiff plastic) in the hole. Dry, no clog felt. All the fluid is dripping out of the floorboard drain holes. The carpet under my super ginormous snow-catching floor mat was soaked with anti-freeze.

Has anyone done this on a V8? How hard are the hoses to get to under the hood? I have access to a mechanic (works at our local stealership) that moonlights for $25/hr, so I could go that route, but I don't know his timetable. I know I can't wait much longer. It is getting cooler out and that means my window fogs up terribly bad on the driver's side only. Of course it has to be on the driver's side - why would it be the passenger side only?
 
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BlazingTrails

Member
Apr 27, 2014
19,409
I've not pulled the dash in a trailblazer yet, but I have pulled several dashes in the past. It seems like voodoo to most people bit it is actually pretty easy removing the dash from a vehicle. I would not be intimidated, once you do it you will also wonder why people are so afraid of the dash.

I would be very careful of the actuators, they are very easy to break.
 

linneje

Member
Apr 26, 2012
404
If you can get the hoses off you would not have to evacuate the AC. There is enough room to reach up with one hand from below (like, through the wheel well), but that is it. How to disconnect those quick connects with one hand, I am not sure. Perhaps if you had someone working from the top to press the wings while the one from below pulls....... ?
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
BT, I'm not afraid of it, just not sure about the hoses on the firewall. I saw a thread (that I can't find now, of course) of a guy that did it in his driveway in Puerto Rico and it wasn't too bad. Ya know, relatively speaking...

linneje, you have to evacuate the A/C as the evaporator is in the same box as the heater core and it all comes out as one unit, so all the lines have to be removed. I wish there was an easier way. My last truck (a GMC C1500) was very easy - remove the hoses on the firewall under the hood, pull the panel in the passenger floorboard, pull the heater core out from under the dash. Not so with these beasts.

Oh, well. If I do it, I'll post pics. If the mechanic does it, I'll let you know when it's done. :2thumbsup:
 
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littleblazer

Member
Jul 6, 2014
9,265
After doing the heater core in the vette I wish I could have pulled the dash. Most of that was up side down in the foot well working through this tiny mirror with to swivels on a 1/4 inch ratchet to get those top screws on the heater box. Can't feel for them and can't see them with a mirror but you could see the clip it screwed into. So you guessed on position....

Anyway, from those who have pulled the dash it isn't terrible but is time consuming from what I've read. As far as the hoses, I don't know how they hook up or where, I just don't recall. Maybe cut off the nipples with something and then you can manipulate the ends to remove the barbs and work it that way?
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
littleblazer, I hear ya. I have done jobs like that on vehicles. Like I said at the beginning, we need an "Engineer in the garage" day. I'm just not sure about getting access to the hoses to get them loose and then getting them back on - correctly. It's always easier to take something apart and let fall, but then getting it back in the right position at the right angle (with the o-ring in place)... well, we all know how that can go.

I think what I may do is remove the bracket that holds the drier and shift it a little and see if that gives me enough sight down there to feel confident. I could always just do it and deal with it as it comes, but I would hate to get the job 99% done and then be stymied. I'll grab some pictures later today so you I6 guys can see what I'm dealing with.
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
As promised, here are 3 pics of how it looks from the top on the V8.



Getting a little closer, it doesn't get much better.



Here you can see the one of the a/c lines on the top, one of the bottom hoses (heater) and the drain. I stuck the camera down where I snaked my arm in the other day. You certainly can't see that from the top. I'll have to bring a bright flashlight out and see if illumination from one angle allows me to see anything from another angle.

 

linneje

Member
Apr 26, 2012
404
linneje, you have to evacuate the A/C as the evaporator is in the same box as the heater core and it all comes out as one unit, so all the lines have to be removed. I wish there was an easier way. My last truck (a GMC C1500) was very easy - remove the hoses on the firewall under the hood, pull the panel in the passenger floorboard, pull the heater core out from under the dash. Not so with these beasts.

Yikes, sorry I had no idea. I was looking at it anticipating flushing my heater core, not replacing the core. I hope that it doesn't get to that for mine.
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
OK, in rereading the thread on the OS and looking through the service manual, I do believe I'll do it myself. I think once I get the A/C discharged, I can move the drier and the overflow reservoir and have more room. I called a local shop and he said he would charge $50 to discharge it and recharge it when I'm done. Hopefully I'm not down any freon so I don't have to pay for any makeup volume.
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
Yikes, sorry I had no idea. I was looking at it anticipating flushing my heater core, not replacing the core. I hope that it doesn't get to that for mine.

Yeah, I think for flushing it in place, you should be able to just pull the hoses and flush it out.
 

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