So the dashboard in my 99 GS3 was removed TWICE this year. The first time mechanic changed just the heater core and resealed the evaporator box, after another thought I decided to repeat the process and change the Evaporator Core, expansion valve, and instead of silicone re-glued the white evaporator box seams with JBWeld.

 

i recently just did this also, here is a very detailed DIY

https://www.clublexus.com/forums/gs-...iy-w-pics.html

 

It's a very thorough process, you literally have to stay over mechanic and tell him what to change (o-rings, expansion valve, re-insulate the outer layer of the valve because it gets all torn, getting a/c condenser out without removing the radiator). And I didn't trust the Toyota silicone after seeing it peeling off easily so just glued almost all seams of the evaporator box.

 

These evaporator removal guides are getting useless anyway as more GSs are going to junkyards or owners unable to justify the cost of this expensive repair vs. the current value of the car.