dodgethis Posted May 12, 2014 Report Share Posted May 12, 2014 Hey, Has anyone replaced a heater core? I came into the vehicle and found coolant leakage on the passenger side floor. I have verified that its coolant, tastes sweet I am hoping I can bypass it since its summer, as I assume replacing the core involves tearing apart the whole dash. I didn't see a write up, but once I find some information I'll take some photos and add it to the How to article. This is on the 98 lumina. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 12, 2014 Author Report Share Posted May 12, 2014 Here we go: [h=1]Heater Core Replacement[/h][h=3]Removal Procedure[/h] Remove the fuel injector sight shield if equipped with 3.8L. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical - 3.8L. Drain the coolant. Refer to Draining and Filling Cooling System in Engine Cooling. Disconnect both of the heater hoses at the heater core. Refer to Heater Hoses Replacement or Heater Hoses Replacement . Remove the left and right instrument panel insulators. Refer to Insulator Replacement - Instrument Panel (I/P) or Insulator Replacement - Instrument Panel (I/P) in Instrument Panel, Gauges, and Console. Remove the knee bolster bracket. Refer to Bracket Replacement - Knee Bolster in Instrument Panel, Gauges, and Console. Remove the instrument panel compartment. Refer to Compartment Replacement - Instrument Panel (I/P) in Instrument Panel, Gauges, and Console Remove the front floor console if equipped. Refer to Console Replacement - Front Floor in Instrument Panel, Gauges, and Console. Click to Enlarge Remove the lower heater duct bolts. Remove the lower heater duct. Click to Enlarge Remove the heater core cover bolts. Remove the heater core cover. Click to Enlarge Remove the heater core tube strap bolts. Remove the heater core bolt and bracket. Remove the heater core. [h=3]Installation Procedure[/h] Click to Enlarge Install the heater core.Install the bracket and straps to the heater core:Caution!Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Install the heater core bolts.Tighten Tighten the heater core bracket/strap bolts to 1.5 N·m (13 lb in). Click to Enlarge Install the heater core cover.Install the heater core cover bolts.Tighten Tighten the heater core cover bolts to 1.5 N·m (13 lb in). Click to Enlarge Install the lower heat duct.Install the lower heat duct bolts.Tighten Tighten the lower heat duct bolts to 1.5 N·m (13 lb in). Install the instrument panel compartment. Refer to Compartment Replacement - Instrument Panel (I/P) in Instrument Panel, Gauges, and ConsoleInstall the knee bolster bracket. Refer to Bracket Replacement - Knee Bolster in Instrument Panel, Gauges, and Console.Install the left and right instrument panel insulators. Refer to Insulator Replacement - Instrument Panel (I/P) or Insulator Replacement - Instrument Panel (I/P) in Instrument Panel, Gauges, and Console.Install the front floor console if equipped. Refer to Console Replacement - Front Floor in Instrument Panel, Gauges, and Console.Connect both of the heater hoses at the heater core. Refer to Heater Hoses Replacement or Heater Hoses Replacement .Refill the cooling system. Refer Draining and Filling Cooling System in to Engine Cooling.Install the fuel injector sight shield if equipped with 3.8L. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical - 3.8L. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 15, 2014 Author Report Share Posted May 15, 2014 Also, If anyone is looking for a write up with pic, this site will really help http://www.gmwbody.com/forum/faq/writeup-heatercore-replacement-94-96-gp-3100-wpics/?PHPSESSID=5af1724ae0d84752ccc7c6f17c8b7bb3 Quote Link to comment Share on other sites More sharing options...
j_mezz Posted May 15, 2014 Report Share Posted May 15, 2014 Cool, thanks for posting all this, I'll be doing my heater core very soon. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 17, 2014 Author Report Share Posted May 17, 2014 Guys, What is it behind the heater core? I have everything torn apart in order to replace the heater core but i noticed rust on one of the screws thats holding whatever that is behind the heater core. Could I leak from that? http://img175.imageshack.us/my.php?image=img2827if9.jpg Right now, I have kept the climate control on Max A/C, thinking it would slow the leak, and I haven't seen any leak since I tore the car apart. I guess I can try to turn on the heat, or defrost and see if it makes a difference. Quote Link to comment Share on other sites More sharing options...
pitzel Posted May 17, 2014 Report Share Posted May 17, 2014 Not really understanding why you think tinkering with the AC settings is going to do anything. The heater core receives a full blast of engine coolant all the time. There is no regulation of coolant coming into the heater core. Whether you extract any hot air from it or not is a function of the position of one of the variable doors in the airbox, and of course, the temperature differential between the air and the coolant. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 17, 2014 Author Report Share Posted May 17, 2014 Not really understanding why you think tinkering with the AC settings is going to do anything. The heater core receives a full blast of engine coolant all the time. There is no regulation of coolant coming into the heater core. Whether you extract any hot air from it or not is a function of the position of one of the variable doors in the airbox, and of course, the temperature differential between the air and the coolant. Yea, that was ignorant of what I said. Well, it doesn't make sense where I could be leaking coolant that came over to the passenger side. If the heater core is always receiving coolant, I would expect it would be visible of coolant everywhere. I didn't see that. I did see however, a screw that is severely rusted, to the point that a socket wont fit over it to remove whatever it is behind the heater core. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 19, 2014 Author Report Share Posted May 19, 2014 Heater core is replaced. It isn't that bad. Basically the two hoses have to disconnected from outside the cabin. Then unbolt the straps holding the pipes together in the car. The heater core should then pop out. I will say this it was harder trying to put the outer shroud back over the heater core. I had to cut the extruded tabs of the enclosure, because the after market core was thicker than the OEM. I ended with an extra screw after it wall said and done. Quote Link to comment Share on other sites More sharing options...
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