I just got a 2005 Corolla and am lost! There are 2 places to add/top-up coolant....which one do I use, one has a metal lid (that says don't open when hot, on the left) and the second has a rubber cap (over-top a kind of plastic container, onm the right)? Why are there 2 places?

I opened the metal lid and the there was a little dip stick with coolant that was a dark black/red colour! So I opened the rubber cap and added the coolant that i had left over from my old car (pre-mixed green colour)......was that a bad thing to do? What will happen!!??

Any help is appreciated! Thank you!

THINKING 1 IS YOUR ACTUAL RADIATOR AND THE OTHER ONE IS YOUR RESERVE THEY SHOULD BOTH BE FILLED TO THE APPROPRIATE LEVEL

That was probably not a good idea. Some cars are only supposed to have the red antifreeze, plus I heard mixing them could cause internal corrosion. It sounds like it should be changed anyway if it's starting to turn blackish red. Unless someone previously mixed some green stuff in there than that might explain the color, but it should be changed anyway.