Okay 690 owners, heads up! Albie's incident has uncovered a design flaw with the cooling fan. I've got 1500 miles on my 690 and just pulled off the fan to check the wear, and it has already started to make slight grooves into the core tubes where the plastic rubs against it. If you don't do something about it, you WILL eventually spring a leak, just as Albie did... it's just a matter of time. It will likely occur after your warranty is up, though, so you should address the problem now.
The problem is that KTM did not use a soft, flexible air seal (like a rubber gasket) to fill what should be an intentionally designed small gap between the radiator and the cooling fan housing. Instead, they designed the fit such that there is no gap (or a very, very thin one), such that the hard thin plastic ring of the fan housing lightly contacts the core of the radiator when fitted. Any movement caused by vibration or shock is translated into friction between the fan housing and radiator core, eventually wearing a hole into it. Bad design... period!
I am going to remove an 1/8 inch or so of the ring on my fan housing and fit a split rubber strip (like what protects the fairing from rubbing into the dash piece on an LC4 Adventure, or like you'd put on the edge of your car door to protect it from chipping paint if you open it onto something) to fill the air gap and then refit it. I'll post pics when I get it done.