There is no chance 2004 Xsara Picasso engine will work efficiently with bad cooling. Before choosing fluid note that engine code RFN(EW10J4) and volume of 2.0 were installed to your car in 2003. For sufficient use of Citroen Xsara Picasso you need to use suitable antifreeze. Make sure you service system at Citroen with installed 1.6 engine correctly. It’s important to use 7 liters of coolant which has Red color.
To endure car life take only Red antifreeze and pour not more or less than 7 liters. There is a big plus in servicing 2003 Citroen Xsara Picasso with all regulations. It’s obvious that every NFU(TU5JP4) motor needs good service as stated by Citroen in instruction. 1.6 Xsara Picasso motors of 2004 year will serve more by optimal service.