My mother-in-law asked me to flush out her cooling system on her 1999 Explorer. I have not had a chance to look at it yet. She said it has the factory coolant in it.

Does it matter if it had red coolant (not sure if they came with the red stuff) and I put in green?

I really don't wan't to flush it all out to change types if I don't need to. My plan was to just drain the old and buy some 50/50 premix Prestone and top it off.

Any tips?

 

If you are not draining all of it, and you put 50/50 in it, it may be too dillitued depending on where you live. Spend a couple of extra $$ and get an aniti-freeze tester and measure your mix after you run it with the new fluid in it.

 

Sorry I should have been more clear. I do plan on draining all of the old coolant but didn't want to "flush-out" the system, like with a garden hose. I was thinking that would introduce plain tap water-not distilled.