Blazer Heater Core Replacement Dash Out...now What?

mychevyvan · February 7, 2010

Anyone who knows how this is done is a stud! I am looking for help in the details of what needs to be removed to get to the heater core of my 98 blazer. I have the dash out and am looking at the hermetically sealed box, scratching my head. Chilton's is real vague and other sources talk about removing the fender and AC and bolts engine side... REALLY? Is it all that? Thanks for any help you can give this finacially challenged DIYer!

Nytemare · February 7, 2010

Anyone who knows how this is done is a stud! I am looking for help in the details of what needs to be removed to get to the heater core of my 98 blazer. I have the dash out and am looking at the hermetically sealed box, scratching my head. Chilton's is real vague and other sources talk about removing the fender and AC and bolts engine side... REALLY? Is it all that? Thanks for any help you can give this finacially challenged DIYer!

Yes you have to remove it from the engine side of the fire wall. Its inside the black box that's there. Estimated shop time for this job is 9 hrs, I have done it in 5-6 hrs before.

Get yourself a Haynes manual...they're much more user friendly for someone who doesn't do this sort of work all the time.

mychevyvan · February 7, 2010

Anyone who knows how this is done is a stud! I am looking for help in the details of what needs to be removed to get to the heater core of my 98 blazer. I have the dash out and am looking at the hermetically sealed box, scratching my head. Chilton's is real vague and other sources talk about removing the fender and AC and bolts engine side... REALLY? Is it all that? Thanks for any help you can give this finacially challenged DIYer!

Yes you have to remove it from the engine side of the fire wall. Its inside the black box that's there. Estimated shop time for this job is 9 hrs, I have done it in 5-6 hrs before.

Get yourself a Haynes manual...they're much more user friendly for someone who doesn't do this sort of work all the time.

Thank you for the quick response. I will look into getting a Haynes in the AM. Aren't I supposed to be looking at the black box found under the dash? I will shoot myself if I didn't need to take the dash out!

grose67 · February 7, 2010

I have the information but cant seem to find a way to save it from my manual to post it.

mychevyvan · February 7, 2010

I have the information but cant seem to find a way to save it from my manual to post it.

I would appreciate all the help I can get! Please let me know if you find a way to post the info or as soon as you might have some time, share the less obvious but crucial details it describes.

Thank you!

grose67 · February 7, 2010

Try these links.

http://127.0.0.1:9001/servlets/BlobShtml?S...mspsdsubkey=581

http://127.0.0.1:9001/servlets/BlobShtml?S...8204#ss1-891336

mychevyvan · February 7, 2010

Try these links.
http://127.0.0.1:9001/servlets/BlobShtml?S...mspsdsubkey=581

http://127.0.0.1:9001/servlets/BlobShtml?S...8204#ss1-891336

I was not able to connect to the links you gave. Thanks for trying...any other help?

Nytemare · February 8, 2010

Anyone who knows how this is done is a stud! I am looking for help in the details of what needs to be removed to get to the heater core of my 98 blazer. I have the dash out and am looking at the hermetically sealed box, scratching my head. Chilton's is real vague and other sources talk about removing the fender and AC and bolts engine side... REALLY? Is it all that? Thanks for any help you can give this finacially challenged DIYer!

Yes you have to remove it from the engine side of the fire wall. Its inside the black box that's there. Estimated shop time for this job is 9 hrs, I have done it in 5-6 hrs before.

Get yourself a Haynes manual...they're much more user friendly for someone who doesn't do this sort of work all the time.

Thank you for the quick response. I will look into getting a Haynes in the AM. Aren't I supposed to be looking at the black box found under the dash? I will shoot myself if I didn't need to take the dash out!

No you need the dash out too.

grose67 · February 8, 2010

Try these. You will have to blow them up some.

mychevyvan · February 8, 2010

Try these. You will have to blow them up some.

That is cool! I believe this will help complete my project. Just when I feel like I'm in over my head you guys pull me up. You're the best!

grose67 · February 8, 2010

Took a little copy and paste and a few different programs but I finally got it! There has to be an easier way. I'm glad I could help.

mychevyvan · February 15, 2010

Took a little copy and paste and a few different programs but I finally got it! There has to be an easier way. I'm glad I could help.

George, that was impossible for my old eyes to read... if I blew it up it got all pixelated and funky. Thank you but I only made a little progress to date (one bolt removed from the cut out I made in the AC evaporator/blower resistor engine side and one bolt removed from the lower right corner of the heating/ventalation module inside the vehicle). Can you or ANYONE tell me how many more bolts and where they are located and how to remove them so I can FINALLY get this module out? I just want to get my blazer out of my friends garage and on the road again without becoming suicidal or homicidal! Important note: This is a 98 Blazer 4X4 WITH the automatic climate control system!

grose67 · February 16, 2010

When I can get to my home computer I will see what else I can do. Can you PM me with a regular email address? That may help me send the info.

grose67 · February 16, 2010

1. Remove the heater/vent module.

Heater Module - Pics 5 thru 8

<LI type=1>Remove the instrument panel. Refer to

Instrument Panel (I/P) Carrier Replacement in Instrument Panel, Gages and Console. <LI type=1>Drain the engine coolant. Refer to Draining and Filling Cooling System in Engine Cooling.
On vehicles with automatic climate control only, cut the outer layer of the A/C evaporator and blower module in order to access the service access cover<LI type=1>On vehicles with automatic climate control only, remove the service access cover mounting screws (1). <LI type=1>On vehicles with automatic climate control only, remove the service access cover (2).
On vehicles without automatic climate control, remove the blower motor resistor. Refer to Blower Motor Resistor Replacement .
Remove the heat/vent module mounting bolt through the blower motor resistor or service access cover opening.<LI type=1>On vehicles with A/C only, remove the right wheel house panel. Refer to Wheelhouse Panel Replacement in Body Front End. <LI type=1>On vehicles with A/C only, raise and support vehicle. Refer to Lifting and Jacking the Vehicle in General Information. <LI type=1>On vehicles with A/C only, remove the front right tire. Refer to Tire and Wheel Removal and Installation in Tires and Wheels. <LI type=1>On the Utility only, remove the A/C evaporator and blower module heat shield screws. <LI type=1>On the Utility only, slide the A/C evaporator and blower module heat shield toward the front of the vehicle. <LI type=1>Remove the 2 lower heat/vent module mounting nuts. <LI type=1>On the Utility only, remove the A/C evaporator and blower module heat shield bracket.
Remove the bottom right heat/vent module mounting bolt from inside the vehicle.<LI type=1>On vehicles with a 2.2 L engine only, remove the engine wiring harness bracket located at the rear of the intake manifold. Refer to Valve Rocker Arm Cover Replacement in Engine Mechanical - 2.2 L. <LI type=1>Remove the HVAC module mounting bolt located at the lower left side of the heater core to heater hose connection. <LI type=1>Remove the HVAC module mounting nut located at the lower right side of the heater core to heater connection.

Important
The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module.

<LI type=1>On the Utility only, loosen the HVAC module mounting studs until the threads are free from the heat/vent module. <LI type=1>Disconnect all of the electrical connectors from the HVAC module. <LI type=1>Disconnect all of the vacuum lines from the heater assembly. <LI type=1>Disconnect the heater hoses from the heater core.
Remove the HVAC module from the vehicle.

Heater core pics 1 tru 5