Not sure if this is the right section. Also going to be kinda long, sorry guys.
Just had to put a heater core in my 2018 ES 5sp with 61k miles. I lived in FL until 2021, so never needed heat.
Winter of 2021/22 in South Dakota, the car was warm (just warm). I assumed just had poor insulation and a small engine. I never have passengers. I also hadn't lived in a cold place in about a decade so my memory of cabin temp was fuzzy.
Winter of 2022/23 it was much worse, glass was refreezing with my breath unless I'd been driving like 30min, passenger side was very hard to get/keep defrosted. It was also a polar vortex and I was working nights, so I assumed the car just couldn't handle the cold..bought a block heater but thought it strange it didn't seem to do much for the inside.
Towards the end of that winter, the passenger side wouldn't defrost and I realized something wasn't right. I started feeling around and noticed the passenger side felt only barely warmer than outside air. If it was 20 outside, the vents felt about 40.
Sort of confirmed it by reazling the car got way, way, warmer on recirc. Obviously not a solution. Didn't temp probe it. Car was also 1 month beyond warranty when I realized it, so hard numbers didn't matter. All signs pointed to the core, core was getting yanked.
That was an absolute nightmare to install working with an untreated fractured right hand! That being said, I got it done and the car felt immediately warmer on the passenger side.
**Also, DO NOT reuse the coolant drain bolt gasket if possible.
I had it off twice, the initial drain to do the core, and, then a second drain of distilled water.. I was driving 10 miles home (highway speeds) from where I did the work, and began smelling coolant about 2 miles from home, there's no real place to stop so I just cranked the heater and didn't stop. No lights came on the dash, Torque showed coolant temp climb from 195 to 201 and sort of slowly go between the two..
When I got home I Noticed the carpet where the core tubes come through was damp and assumed I buggered something up and started looking for leaks on the lines and core.. then I popped the hood and noticed the entire insulation along the firewall was soaked, as well as the lower crossmember area. I have to wait for someone to give me a ride tomorrow, but I couldn't see any other place it could have came from. Guessing it sorta made a squirt jet out of it.. Block was near empty and the radiator cap was ice cold. Hope that little bit of abuse didn't do anything bad. It wasn't leaking for the 30 minutes it idled with the cap on before I left, so it must've needed some RPMs to get it to start spraying.
Don't know if anyone else has had a 2018 with a core issue yet, but here's one. And sorry I umm don't have the old core, long story.😅