03 galant coolant leaking on passenger side

Most likely the heater core is leaking. This heats the air coming into the cabin of the vehicle from the HVAC box using heat from the engine, and coolant flows through the unit. Unfortunately this usually means dismantling a fair portion of the dash to replace, and if you are a big dude like me with hams for hands, it’s not fun.

Aye, it’s leaking on the floor of your car and evaporating into the cabin of your car. A word of caution: antifreeze fumes are EXTREMELY toxic. Do whatever you have to do to not breathe them.

Take a pic and upload it to your computer, then at the bottom of the post box, there should be an option to upload the pic to your post. I would do a good drain and fill/coolant flush while you have the system open anyway. Most importantly be sure to burp the system once you are finished. Air in the cooling system can cause alot of issues. Here’s a video that demonstrates what I’m talking about, and also one on flushing a heater core that might give you some idea what you are looking at:

Heater core flush:

Bleeding cooling system:

Good luck man.

Get a good service manual, and you’ll do fine. It’s not the worst job, but not the best. BE PATIENT, especially when you are working up under the dash, so you don’t break stuff. I have to walk away from stuff like this and take a break on occasion, and you may too. Don’t let the machine beat ya bro. I’m rooting for ya.

^^Thats a good tip college man

Honestly that’s what I would have done as a temporary solution so well done. You’re probably going to need heat though. Unfortunately you’re probably going to have to remove the entire dash and HVAC assembly to get to it. This also means that you’re going to need to evacuate the AC system if it has a charge in it since you’ll likely have to remove the evaporator along with the heater core. It’s a big job for sure but not impossible, take your time and keep your parts and fasteners organized and you should be fine.