Please excuse my ignorance, but is there a certain spec of antifreeze I should be using to top up the coolant in my 306 HDI. I just want something that will mix fine with whatever is currently in the system (changed by previous owner).
Mine is the red coloured antifreeze, other than that I don't think I've ever had to top it off more than a couple to times in 10 years of 307 ownership (garage do the changes when needed). My trusted motor factor gave me the right stuff.
Don't mix the types. If you have blue coloured coolant (the cheaper variety), stick to it.
The red stuff is better (can be left for 5 years or more) but if you add blue antifreeze to it, you can get a sort of gloop forming because they have different chemical construction.