The radiator in my 2002 ford ka needs topped up. The problem is that I've only just bought it, so I don't know what kind of antifreeze is already in there. I don't have time at the moment to figure out how to drain the whole system and replace it, so is it safe for me just to top it up with tap water for now, then sort it out properly in 2 or 3 weeks?
Thanks in advance!