Chaps I think that the word coolant is a little miss leading.
I prefer to call it corrosion inhibitor. (or anti freeze, anti boil, antipesto etc etc etc
For the best cooling / heat transfer, pure water is best.
HOWEVER !
Then you have the issue of higher temp and cavitation, thus the "coolant" has additives to prevent this, and corrosion, and stuff to stop minor leaks, stuff to stop if freezing at 0 deg, and boiling at 100 etc etc etc.
Personally I use the motorcraft r13b concentrate with pure water.
Have seen ea falcon heads and head gaskets with 180k on them before being replaced that only ran that stuff.
Most heads I did were around 80 to 120k if they were lucky.
Its about 10 bucks for 500mls and that does most cooling systems, sorry I dont have a spare bottle handy to see how many lts that does.
Again thats just my opinion.
Happily used it for many vehicles, including familys and my own with good results.
If your cooling system is not working, its not exchanging heat properly, and the reasons for that can be many and varied.
Mostly from blocked cores not exchanging heat properly, thus when demand is put upon it, it cant cope and the overheating begins.
Sometimes a basic flush can help that, but the best thing to do is take out your rad, get it rodded by a rad chap, flush out your cooling system including your heater core, and refit and refill with fresh stuff of your liking.
That way you have removed any gunk (different coolants mixed together can be nasty and quickly block up a rad core) and casting sand, left overs from the head repair etc etc etc from the block, and the rad, and its got fresh stuff in it and it can get on with its job efficiently without any contamination to upset it.
hope that helps a bit.
Trains
