Thanks for the information, Dennis!
I am planning to change the water rail seals. I am thinking between two options: 1." the conventional" which involves taking off the intake manifold, and 2: without removing the manifold as described here: [[xj40] Water rail gaskets DIY -- w/o removing inlet manifold Part I]
By the way, I got the A/C system charged with 920 grams (32 oz) of R134. The system did not indicate leaks during the pressure test and with the hand held refrigerant leak detector after the charge. I had replaced the drier, compressor oil (PAO 68, 210 cc), O-rings of the compressor connection pipes, O-rings of the thermal expansion valve connections and O-rings of the drier connections. I had also installed R134 retrofit adapters. I had also checked that the compressor clutch engages and the compressor sucks. Of course, time will tell whether the system really works in the long run.