When I was preparing to remove the engine I was unable to disconnect the dipstick tube from the engine, old arthritic fingers don't help, so I cut the tube and repaired it with a piece of rubber fuel line... just the right size.
Today I installed new coolant reservoir, good thing the old one was about to fail...
I can't believe I did this a couple of years ago with the engine in the car, it was a huge PITA even with the engine out.