4th Gen A/C Leak Detection
 

Can a leak detection of freon be determined if an expansion valve is stuck closed? It is my understanding that the freon needs to circulate through the entire system in order to determine where the leak(s) may be. Comments appreciated.

If the leak is in the high pressure line between the compressor and the expansion valve, then yes. Otherwise no.

How do you know the expansion valve is plugged? The refrigerant line going into the expansion valve should be hot. The line leaving the expansion valve should be cold.

https://www.swtc.edu/Ag_Power/air_co...sion_valve.htm

A symptom of a blocked expansion valve is evident once you turn your a/c off and the low and high side pressures don't equalize...If the High side remains exceptionally higher than the low(suction)side then you may have a blocked expansion valve problem...Get your Low/High recommended pressure at a specific Air temperature and humidity using a R-134 pressure chart and see where you're at...