How hard is it to replace the heater core on a 1995 GMC Sierra 1500?

[Tx1Longhorn]

It has the regular cab with air conditioning and a 5.7 liter engine.

 

[Mr. KnowItAll]

http://www.automd.com/repaircost/

It's time consuming, and a pain in the asss, but it's doable.

 

[gmcjosh]

I had my mechanic do it after it locked up and pushed all the water in my cooling system and I had to also replace all of the top end gaskets as the engine got baked when it happened.

 

[Molson02536]

It has the regular cab with air conditioning and a 5.7 liter engine.

The heater box in that is the same as the 1988-1998 Chevrolet C/K trucks and the repair manual will instruct you to remove the heater box which requires lifting the passenger side dash. But that is unnecessary and is a huge waste of time.

The heater core on that is accessed by removing the bottom cover on heater box and the reason the repair manual instructs to remove the heater box is because removing and replacing a screw on the firewall side of the bottom lid is problematic with the heater box in the vehicle. But removing it with the heater box in the vehicle is doable. It is replacing it when reinstalling the bottom lid which is really tough but most mechanics will not bother to replace it when heater core replacement.

1. Disconnect the heater hoses at the firewall under the hood.

2. Remove the passenger side kick panel and door sill and pull the carpet and padding back. This is necessary not only to avoid spilling coolant on the carpet when removing the heater core but also because the thickness of the carpet and padding closes the gap between the heater box and firewall and obstructs access to the screws on the firewall side of the bottom lid.

3. Remove the 6 screws securing the heater box bottom lid. One screw on the firewall side of the bottom lid is recessed in a well between the heater core inlet and outlet tubes and the other 5 screws are on the lip of the bottom lid, 1 on the front lip, 1 on the right lip, 2 on the left lip, and 1 on the firewall side lip. It is the 1 on the firewall side lip which will be a bear to access but removing it is doable using a shop light and a mirror to see it and that is the 1 which most mechanics will not bother to replace when reinstalling the bottom lid.

4. Remove the bottom lid.

5. Remove the screw and clip which secures the heater core and remove the heater core.

To install, just do it in revers and take pictures as your take things apart so you have reference to how things go back together. Thank god for cell phone with camera.

 

[justin caise]

Awesome info! And it is true - no need to tilt the dashboard forward or otherwise remove it - at least not on my 1998 GMC Sierra.

I just removed the bottom of the heater core box by the method described above and verified that it is not leaking. (Still don't know where the coolant is going but there's no liquid in my box.)

True I don't need the screw in the rear.

Saved me money and time. Thanks.