Pipe corrosion is a bummer but you should be able to prevent it by installing suitable magnesium anode plugs in the block. I do remember seeing such items somewhere for 4 and 6cyl engines a few years back, but you can make your own custom jobs on a lathe from home water heater anodes -I've seen them to be ~1" thick and ~10" long (c'mon MD, no smartass ideas here...
![Twisted Evil :twisted:](./images/smilies/icon_twisted.gif)
).
Already corroded parts can be simply repaired with alloy welding, no problem.
Those inserts are a nice idea Maurizio, for something you open up
frequently. How many times will you have to disassemble the thermostat? I think M8x1.25 is a more practical solution in this case. We use these inserts when necessary to replace corroded/broken/stripped long M12 block/head studs on otherwise good 4cyl blocks. We get them from Wurth and they are called 'time-sert'.
Jim K.