98 chevy truck heater core replacement?

Discussion in 'Chevy Truck Talk & GM News' started by ck1500dess, Nov 30, 2011.

  1. ck1500dess

    ck1500dess New Member

    How had is it to replace heater core on 98 pick-up?
    do you get it from the inside cab or outside firewall?
  2. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    It's a pretty good sized job. It's coming out from inside the cab. You have to let the steering column down, and pull the dash back. Start by removing the passenger seat so you have some room to work. If your truck has AC, you will need to evacuate the system and disconnect the AC lines at the firewall. This turned out to be one of the most difficult/time consuming steps for me. I had to heat the fittings to get the large upper one at the accumulator. The small lower one still twisted off even after heating it. It would be wise to have a new Accumulator on hand, just in case. You'll be surprised how badly they corrode, especially if you live near pine trees and the needles get in there. The fins on mine turned to powder just touching them. The Haynes manual gives teh general overview of the project, though it fails to mention there is one bolt on the INSIDE holding the duct box to the firewall. It's at the very top of the box, you can see the bolt end sticking through the firewall from the engine compartment.

    So yes, it's a big job, though nothing terribly difficult. Mitchells allows about five hours. I did mine in about the same, which I thought was OK, although I didn't vac the AC down and refill.
    Last edited: Nov 30, 2011
  3. Caddiac

    Caddiac Epic Member 5+ Years 1000 Posts

    There has been a number of forum posts on this and similar topics. I am not sure but I thought there was a thread that indicated it could be done without going the distance 2Cor517 describes. But that is what the factory manuals call for and by the looks of it, 5 hours would be a a pretty good pace for something of this magnitude.
  4. pj2774

    pj2774 New Member

    I just did one on a 1990 Chevy Step Side and it was pretty easy. It was located below the glove box. Drained the coolant, removed the screws for the plastic shrouds, disconnect the inlet and outlet hoses on the firewall then one clip. Pulled it straight out. Reverse process to install. Add new coolant. It started to overheat at first due to some trapped air. Once I vented it out it was good to go. Yep, about 2 or 3 hrs.
  5. CustomFabMan

    CustomFabMan New Member

    Wow I must be good then because I did mine in 30 minutes, drained, disconnected, removed, installed the new heater core and refilled the coolant test drove it and went on my way. My truck is a 1997 Chevrolet Z71 4x4. I simply went under the dash by the glove box after I drained the system and disconnected the hoses, then I removed the screws holding the top of the heater core into place, now the screws towards the back are a PITA but I have ratcheting wrenches and long needle nose pliers and was only under my dash for about 15 minutes with the glove box out! Oh ya my truck also has a/c and I did not touch the a/c system pulling the dash out just makes it easier to get to the back screws but look at them, go to parts store or toolbox, buy ratcheting flex head wrenches and long reach needle nose pliers, go back under dash and remove screws, I used just a socket on the screws I couldn't get the wrench on but I have big fingers so if I can do it certainly many others can too! Here is a link to one minute 37 second YouTube video showing how I did it, not sure why so many people are pulling the dash out for this!
    Last edited: Nov 29, 2012

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