I have a 2.5 long nose TDI Velle, and on the back of the radiator fans are some louvres (?) that are connected to a sort thermostatic spring arrangement at the top of the rad. Presumably these are supposed to stay closed until the van gets up to temp, and then the thermostats allow them to open. Anyway, I was driving yesterday (fast country roads, no traffic) and whilst the tempt gauge sat around 90, when I got home the fans were on, and when I looked the vent things (whatever they're called!) they were still shut. I've manually turned them so they're both now fully open, but does anybody know how they're supposed to work, or should I just leave them open until winter time, or even remove them altogether?