I think I have figured out a way to change the Valve Guide without removing the Cylinder Head.

But, please remember I am not there to see it and I have not had a Mercedes Cylinder Head off or changed any Valve Guides on a Mercedes.

Remove from the Head what ever parts are needed so that you can get at and remove the Valve springs just as it is in picture in the original post.

Rotate the Engine by hand and let the Valve drop down enough so that you can use a Tap to thread the inside of the Valve Stem Guide.
Use a Slide Hammer and pull out the Valve Stem Guide.

Do what ever is needed to clean out the Valve Stem Guide hole.

Rotate the Engine by hand to TDC so that the Valve is all the way up.

You will need some sort of Tube that will allow you to drive in the new Valve Stem Guild and not mess with the Valve.

Slide the new Valve Stem Guide over the Valve Stem and drive it in.

Put on the new seal and assemble the Head.

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84 300D, 82 Volvo 244Gl Diesel