Antifreeze (which type to use) in a 2004 VW Jetta TDI engine

yes you must use VW spec 24.00 gal. all other stuff screws with the insides. I don't know why but saw the bad witeups on using other stuff and my mechanic made the mistake once on some ones car cost him 400.00 to fix

You need to use a glycol concentrate called G12. It can be purchased from any VW or Audi dealer and runs about $17-19 a gallon. It MUST be mixed 50/50 with distilled water and is a 'lifetime' coolant/anti-freeze, which means that once in, never needs to be flushed, cleaned, or replaced unless some other procedure requires for part (or all) of the system to be drained. G12 is specifically engineered to be friendly to the different types of metals found inside of VW/Audi/etc motors. In addition to finding it at a dealer, there are two other reputable brands that make it for over the counter sale... Hepu and Petosin. These brands typically sell by the liter, and not the gallon. These days G12 has been updated and is now called G12 plus plus (yes, there are 2 'plusses'), which means that it NOW can be mixed with both the G12 that may have come in your vehicle from the factory, and G11, vw/audi's last generation (1990's) coolant.