i need to know how much coolant i need to buy from SEAT to do a complete change on my 03 Tolly. apart from the drain point are there any other clips that need removing to get all the old coolant out? should i flush the system with normal tap water or just re-fill with coolant and de-ionised water. is G12+ the latest stuff? the local, 30 miles away, SEAT dealer said i only needed 2ltres of the coolant and the rest water, this dosent sound right to me. is it cheaper to by the coolant at SEAT, VW, or Skoda?