my question is i removed the monovalve and saw the diaphram was tron and worn out so i replaced it and have yet to test it out but could there be another reason besides the monovale gone bad that hot air is coming out the defrost vents regardless of temperature and if everything is set to off. it happens in high speed and form driving a while, im on the freeway and hot air will come out. one of my other questions is i found out there is no refrigernt in the system and since im on a budget R-12 is to expensive, i was thinking about converting to R-134A. would i have to change anything if i did reto fit it to R-134A like the reciver drier.Also since there is no refrigernt in it is it the reason for my auxiliary fans not turning on?also were would the drain plug be to drain the remaining R-12 thats still in the compressor[/align]

 

I wouldn't drain the R12 by yourself. Get yourself a mechanic to professionally get the R12 out. R12 destroys the ozone layer.