As mentioned here before, my GTO auxiliary coolers just came off the body for no reasons. Which is more than annoying. It needed a proper fix, but more important, I needed to find the cause first.
You just don’t want this to happen. I found out that the coolant hose was 4,5 cm too long, causing really enormous pre-tension pointed outwards. So the firm silicone coolant hose forces (together with engine vibrations) caused the Sikaflex glue to brake, and worked the auxiliary cooler off the body. I shortened the hose, properly cleaned and degreased the cooler, and re-glued it firmly again myself using black Sikaflex 552 AT glue. A firm professional glue used by Donkervoort to mount the cycle wings.
In addition I found out that there was a similar problem with the oil cooler on the other side of the body. If you spent such an amount on a car, this should not happen.
Ready to hit the road again!