ok i have put 3 12oz 134a cans plus oil charge and a/c is still not cool enough. low pressure is higher than red (high pressure gage) high prssure is not much above 150 psi, no leaks, do i need to add another can? i retrofitted my 1983 300sd, 190K miles last year with new compressor, dryer, switch, o rings, expansion valve. worked fine until 134a fitting started leaking, then lost all 134a, put new fittings on and now i am having the above problems. i am starting to really hate this car! it is a money pit! but i can not afford another one right now and i need cool a/c for my job! help!!!!