I recently replaced the timing cover seal on my Series II and when I refitted the rad I used a coolant. Previously had used water only. It never gets cold enough to freeze here, it was more to guard against corrosion.
Now when engine is warmed up and running I get a very slow drip from the engine block drain tap, never happened before. I am assuming the tap needs new washers or replacing but my question is this: Does adding a coolant result ina higher water pressure through the engine? seems strange this only started when coolant was added.
Anti-freeze will leak where water doesn't. Here in Canada we see that all the time.
If you used the drain tap to drain the block when you replaced the cover, you may have "disturbed" the tap internals.
Depending on the type of tap it might be possible to dismantle it and 'grind it in' - like you would grind inlet/exhaust valves in, but dont start off with coarse paste! only use the finest as it will only be brass!
Interesting that coolant leaks more than plain water. I think I'll leave it a while and see what happens. If still a prob ESM have new taps at 12 pounds.
At the same time I would recommend Bar's Leaks - stays in the system permanently (water or anti freeze) Presume it or something similar is available in the land on Oz