Straightening valve

Well, I haven't come here for a long time. The car has made 25000 km and goes well, even if it spends or throws water and when it stays low it is hot. The thermostat is fine, the fan and clean radiator and everything, simply spends now or throws it but not where.

Now I'm going to buy a Seat Leon 1.9 TDI of 105 hp and wanted a workshop manual for this car, does anyone have any?