Mine sometimes overheat.. Don't know why.
No coolant reroute(working on this...) ,new radiator... New waterpump.
Just set the temp switch on the ecu to 90degrees.. So far so good..
Might be a mallfunktioning switch (NA 1.6 switch)

http://www.ilmotorsport.de/shop/arti...c09e5f03586d8b


Going to try this one...

 

martijn, you are sure that your t-stat is not sticking and that your fans are turning on?
Only time i had issues with too much heat was due to those two problems, so that's where I look first.