| | 4th gen heater core replacement
This was penned by Viper and it makes a good sticky here. This is for 97 and up cars but will be similar for LT1 cars.
Thought I would write up what it took to do it. Sorry, no pics.
Start by draining the radiator.
Locate 2 heater hoses that go into the passenger compartment.
Remove clips. MUCH easier said than done; this took the longest. Recommend you remove the passenger side coil packs so you can get at it.
Once off, remove 7mm bolt (6mm on a 97/98 car?) between the 2 pipes. Tight fit again, may have to lay across engine to see.
You're now ready to go inside the passenger compartment.
First remove the cover under the glove box. 2 plastic clips and a metal clip at the bottom. I used a screwdriver for all 3.
Now remove the glove box. 3 7mm bolts hold it in.
Now remove the cover to the heater core. 2 7/32 bolts hold it in.
Now remove the clip holding the heater core in, 1 7/32 bolt.
Carefully slide the old heater core out.
Lay it on a workbench with the new one next to it in the same orientation.
There is a rubber gasket and connecting metal piece between the 2 pipes you removed the hoses from in the beginning. Remove and install onto the new one in the same exact location.
Reverse the process for reinstall. Remember to burp the system when refilling with coolant. Turn the heat on. Disregard the nasty smell, it's the new heater core 'burning' in. It did go away after a while.
Core - $80 at Autozone, cap $6.00, fluids $22.00.
Total time till I started putting coolant in - 2.5 hours. Not terrible considering it was just 'let's see what bolts to undo to get this done.
NOTE FROM PAUL BELL: It's said that an aluminum core will last longer than a copper core. An ACDelco core will fit better as it'll match the OEM spec-something that an aftermarket core probably wont.