How Do You Flush the Cooling System?
 

I did a search and came up empty. We have a 1998 Marquis with 4.6L engine. This car has sat for 10 years. Initially the intake cracked and my wife (I didn't know her then) knew enough to shut it down when it began to overheat. Took it to a shop and they confirm the intake was cracked. Fast-forward to 2009. My wife moved from Houston, Tx here to Missouri so we could start a life together. I found a retrofit-kit on Ebay for $200. We installed it and then it wouldn't get fuel . I found the pump wasn't activating at all so I replaced that sucker. Then I got hurt and couldn't do much on it so it sat. Yesterday, I finally got it started and it runs a little rough but no overheating but upon checking the coolant it needs to be flushed and replenished.

I bought a Prestone Flush N Fill kit only to find out that the radiation has no radiator cap, just the coolant bottle. So I went to YouTube and they were no help as all those viewed have a radiator cap.

So, has ANYONE flushed their system and if so, how did you do it?
Thanks Folks!

*** Going to go drain the oil and replace the oil and filter.

Chilton's (1-33) says that you remove the cap from the expansion tank on 1992 and later models (after making sure the engine is completely cool, of course).