Sorry for the late reply...
I used the refrigerant with the UV dye and still couldn't find a leak. The clutch engaged alright and AC was on for a couple of hours. I did some physical check and found a leak (mainly bubbles) on the low pressure valve. I bought a new adapter and replaced the valve. Surprisingly, new valve also had bubbles coming out after completing evacuation and putting more refrigerant. This time around A/C was on for a good 6 days and on the 7th day back to where it all began. Should I replace the high pressure valve also? It'* hard to see if there'* a leak there due to where it'* mounted. Any advise what may be going on?