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Heater Core Replacement

NVW

NVW

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Castor, AB.
I had to change the heater core in my 95 truck, I had hoped I could take the core out without removing the entire heater box. I removed the screws on the bottom of the box but couldn't get the core to move. I then followed the manual instructions of removing the dash and the steering column. After I realized I would have to evacuate the air conditioning I had a second look at what was holding the core in place. There is a shitty little clip that holds the core in place, with it out the core can drop down and be removed.

The whole job could be done in an hour, the removal of all the other crap probably took 6 hrs not knowing what I was doing. I hope this helps any other poor bugger needing to replace a 400 series heater core.
 
Yep, there's an anchor clip on the heater core opposite of the lines going into the core. I did mine in about 25 minutes.
 
Mine broke when I changed it out so I had to come up with a way to anchor it back in there. (This is the aluminum core that started leaking before I got the brassworks core). I think I can change a heater core on these trucks in my sleep now since I’ve been in there so many times in less than a year.


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Ouch! Never fun pulling a dash for no reason. I had to pull the one in our tahoe over the weekend. Was able to replace the heater doors without removing the whole box. Didn't want to mess with the ac lines because I have bad luck with these trucks coming apart. Thanks Ohio!

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Also any one having reoccurring heater core problems. Get one from the dealership. I did mine 4 years in a row, all from Napa. Bough one from the dealership. It's been 3 years and no leaks.
 
If anyone ever has to remove the dash on GMT400, I would advise to replace the recirc. door actuator while you've got it out. _Extremely_hard part to change with the dash in. I saw a post on another forum where a guy changed it with the dash in, but I'mnot that limber anymore. That's the one that when it goes bad, you'll usually hear a popping noise for about 10 seconds after you shut the truck down.
 
56pan said:
If anyone ever has to remove the dash on GMT400, I would advise to replace the recirc. door actuator while you've got it out. _Extremely_hard part to change with the dash in. I saw a post on another forum where a guy changed it with the dash in, but I'mnot that limber anymore. That's the one that when it goes bad, you'll usually hear a popping noise for about 10 seconds after you shut the truck down.
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Just be sure it is a quality brand, AC Delco or whatever brand the factory used. Dont need that filthy bugger acting out shortly after replacing it..
 
The problem that I kept having was that the o-ring where the tubes crimp to the core would leak shortly after installing it. I checked out several cores at the parts counter before I found one that the tubes didn’t move or spin easily. But it didn’t last long either.

If anyone wants a core that should last a lifetime then the Brassworks core that Twistedsteel Performance pointed out to us a couple times would be the best option. It could be easily soldered if it ever got a leak. I like how thick the material is. It’s a heavy core compared to the aluminum cores.

(Edit: I don’t know why the link dont read 1988-99 K1500.......)




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Now that's a nice core. If I ever have heater core problems I`ll be going for that, regardless the cost. I have a huge disliking for crawling around under dash boards and such. Seems I`m always capable of bloodying the top of My head in the process. LOLOLOL
 
Jaryd said:
The problem that I kept having was that the o-ring where the tubes crimp to the core would leak shortly after installing it. I checked out several cores at the parts counter before I found one that the tubes didn’t move or spin easily. But it didn’t last long either.

If anyone wants a core that should last a lifetime then the Brassworks core that Twistedsteel Performance pointed out to us a couple times would be the best option. It could be easily soldered if it ever got a leak. I like how thick the material is. It’s a heavy core compared to the aluminum cores.

(Edit: I don’t know why the link dont read 1988-99 K1500.......)




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Did you finally get the air out of the system???
 
Twisted Steel Performance said:
Did you finally get the air out of the system???
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I have driven the truck and bled the system many times since I talked to you and haven’t gotten much air out of the system. I have the 190* TStats to put in but I haven’t had time to install them and see if that’s the problem. I’m hoping to be able to put them in tomorrow.
 
Twisted Steel Performance said:
Their are also metal replacment gears for that pesky actuator .....
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That would flat solve the problem with that actuator. The failure I've always seen with it is that you'll hear the popping noise for about 10 seconds after you shut off the truck. The other two actuators provide position feedback to the HVAC control head. They only run to their commanded position. The recirc. door actuator does not. It is driven full travel on a time delay inside the HVAC control head. The plastic gears after a few years get old and brittle and the tooth that gets the pressure when it's run full stop pops off, then the drive gear keeps hitting the adjacent gear tooth for the full time delay. Metal gears would sure fix it.
 
That is awesome- always hated the plasticgear stripping out. In Vegas you want the blend door closed 99% of the time and since every mfr make the automated ones always default to open, they wear out quickly.
 
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