When I got the car the most of the ac system was replaced. It was retrofitted to 134. Tried to put some 134 in and it got cold but leaked out in a few seconds. I ran some UV dye thru the system and could not find the leak anywhere. Not under the car, under the hood, under the dash. Assume it's in the giant monstrosity on the firewall. Think its the Evap core area. I see the small bolts on top. Can I access the top of the core the get a better look or do I need to some major dismantling.