How to replace the expansion valve in a 9G Galant WITHOUT ripping apart the dash

Hi all! Skip down to go straight to the how-to!

Quick backstory leading up to this how-to: I recently lost A/C in my 2008 Galant ES. I used diagnostic A/C dye to find the leak, and sure enough there was a large crack on the compressor (looked like the previous owner tried to “fix” it with RTV) that was clearly leaking dye and refrigerant. I replaced the compressor and then had trouble recharging the system. After two 12 oz cans of refrigerant, the high pressure side was barely above 150 psi (in 90° weather). The air was still not blowing cold, so I added a little more refrigerant and got the high-side pressure to 225 psi, but still no cold air. I gave a little throttle and the high side pressure jumped to 500 psi. The problem then became apparent: the expansion valve was bad and was backing up the the system.

Here is where I seemed to have entered uncharted territory. I could not find ANY information on where the expansion valve is located nor forum posts/YouTube videos explaining the process to replace it. I found a YouTube video claiming you need to pull the entire dash to access the expansion valve, then I found a single thread on a 4G Eclipse forum where a guy talked about trying to find a way to access the expansion valve from the engine bay side of the firewall. I don’t know about you, but I am not a fan of ripping apart the dash, so I used his experience to figure out how to replace the expansion valve, so here goes:

1. Safely depressurize the A/C system and dispose of refrigerant appropriately.

2. Follow the high and low pressure lines back to the firewall and remove the 10mm nuts holding the lines in place (one nut per line). This exposes the “adapter plate” that connects the lines from the engine bay to the expansion valve.

3. Move the lines out of the way and you will see a small 5 mm Alan bolt. Remove this to free the adapter plate from the expansion valve. Now for the hardest part.

4. The adapter plate has about 1 inch of foam glued to it on all sides, and then that foam is glued to the the pocket that the adapter plate and expansion valve sit in. This stuff is HARD to remove. We were able to get a razor around the edge of the valve, then used a screw driver to free up as much of the foam as possible. We then threaded the nuts back onto the studs and used two small wrenches as pry bars. After 30 minutes or so of cutting, prying, and digging, the adapter plate came out with the foam.

5. Now that the expansion valve is exposed, remove the two 4 mm Alan bolts holding it to the interior lines.

6. Replace the O-rings on the interior lines and adapter plate, and repeat the steps to install the new expansion valve.

7. I recommend putting the foam back in around the adapter plate, but I did NOT glue it. I just shoved it into place and it seems to seal just fine.

The A/C recharged like normal and the air is blowing ice cold again! Big shout out to my brother who stayed up until midnight with me figuring all this out and working on the car.