O.K. now for some pics...
all valves - a little black because of the cold starts verifying the nasty noise:
No worries about the valves.
First glimpse inside cylinder Nr. 4 - scratchmarks
piston bearing of cylinder 4 - just like new
piston Nr. 2 - small scratches
Nr. 2 again
piston Nr. 4 - oh oh!
Nr. 4 again
and again Nr. 4
inside cylinder 4 - walls are scratched
again inside Nr. 4
and again inside Nr. 4
indside of Nr. 2 compared with the inside of Nr. 1 looking just like new...
Damages on Nr. 4 should be a reason for a coolant reroute
But why are the damages on Nr. 2?
Nr. 1&3 are just like new.
Rods are in perfect shape.
Any thoughts and comments would help me a lot!