Classic coolant?

11 gals.... Make sure you use additive for the dca's.... Buy some test strips.... Very important

 

What color is what is in there now? You do not want to put in additives if it is red!

 

Use Power cool, just like it came with. That is the very best. you can use cheap coolant and then you will have problems. I worked on engines all my life and that is by far the very best. You buy a test strip and if the aditive level is low you just add a bit, to bring it up to 1200 PPM.
I have seen the damages done using DCA4 and even Cat does not recomend it anymore. I found that out when a customer brought in Nal-cool and had us flush his brand new trucks cooling system and add this. 300,000 K later we were changing the head gasket and cutting the block, I had anouther Cat apart right beside it, the liners were like swiss cheese, the Water pump cover was corroded away. The one with the Nal-cool, the liners were like new, the water pump cover still had the machining marks. I added that stuff to all my own equipment.
Just a thought!