1995 SL500 lower pressure valve for air conditioning system

[Gusfazekas]

Need your expertise. How or where can I locate the low pressure refrigerant line and valve on my air conditioning system? I need to check the refrigerant level but not sure what color the valve is. Also, wanted to add some air conditioning sealer into the system, anyone done that with these cars before? I might have a leaking evaporator and I have been told that it is a very labor intensive job and thus very expensive to replace. So I thought I'd try some stop-leak in the system. I welcome any feedback The mysterious green slime that has been oozing from the discharge hose under the car originates in the heater core evaporator housing. So I am trying to figure it out. I sealed the heater core with stopleak and I think it worked because I haven't seen the slime but I also haven't driven the car much since its gotten colder and rainy the past few days. Thanks, Steve