May I fill the windscreen washer unit with fluid suitable for the summer when it still contains fluid for the winter?

All SONAX windscreen washer fluids can be mixed. But: washer fluids for the winter do not optimally work in the summer and vice versa. The products are adjusted to the respective temperature ranges. In addition, washer fluids for the winter require other cleaning substances than the ones for the summer – e.g. for the rapid removal of salt residues during winter or of insects during summer. Hence, it is best to spray the washer fluid tank empty before pouring in the cleaner best suited for the respective season. For the wintertime, we recommend SONAX Antifreeze & Clear view to remove typical winter dirt with only a few wipe cycles. During summer, Xtreme Clear view NanoPro achieves best cleaning results, even in removing insects.