Hate to pose this question, it is so rudimentary.
To drain a '93 6 cyl there is no petcock on the radiator must pull radiator hose. There is an engine drain plug that I suppose you drain first for better fluid control. Which side is the plug on and general location, please?
Draining a radiator was never a big deal, but with environmental rules things become more difficult

 

Frequency overrules thoroughness, as with reservoir only brake fluid changes.

Idk if the plug is pipe thread or not, maybe you need Teflon tape or maybe it uses a crush washer. Either way, here it is according to my Jag manuals.

Picture is for a 3.6. Not sure if this plug exists for all iterations.

 

Side, Please excuse the informality of calling you by your first name.
Picture was great and the write up helped.
On my model I have no petcock and have a cat converter! Jaguar got me again!

 

Those tricksters! Does that drain plug still look to be there at all?

Loads of cars don't really allow for this anyway. Like I said, doing it only partially will suffice with some items like this. Just pulling your lower radiator hose will get plenty enough out. Run some water through to flush it a bit more thoroughly if you wish.

Maybe its worth considering switching to waterless coolant in the future?