I just converted my 1987 740 A/C system to R134. As of yet I have no evidence of leaks or of any system failure. As it stands, here are the quirks I am trying to understand.
1) This system is definitely relative to the outside ambient temperature. The system cools approximately 35-45 degrees F less than the outside temperature. When the temp gauge in my A/C vent reads 110-115F when I get into the car, it goes to 60-70F after a few minutes.However, if the fan speed is on number 1 (low), the temp gauge reads about 48 degrees F. On number 2 it goes to about 58F On number 3 it goes to about 65F On number 4 it goes to about 72F
Of course the actual number depends on the outside air it's cooling, but the air is getting less cool as the fan speed increases.
To test this I also did the same thing in my 2002 Nissan Xterra. It did not blow much colder, but it was a constant 52 degrees on all speeds.
Is there a specific part that would be symptomatic of not being able to cool at all fan speeds? I am guessing the evaporator??
Thanks! Jamie