Today, removed the back zalman heatsink and heatpipe.
Reinstalled the original heatsink on the back. (This one makes contact at the back of the VPU)
Used at the front the zalman heatsink.
Putted a external sensor on the base of the front Zalman heatsink.
My casefan on the side runs on 7V.
Pointed to the top of the heatsink. If I mount a fan which is pointing to the flat side of the heatsink, it could be a better performance. Still have to try.
After running some games, the heatsinks feels like warm. Not hot.
The temp. sensors says 43°C.

I think this is not so bad.
Keeping in mind, less noise than the original setup with standard cooler.