Replacing Dipstick Tube

[William2]

Is it possible to fit a new dipstick tube into the block with the engine assembled on the bench without too much trouble?

[AHM]

Yes!

Warm the casting locally with a blow lamp.
Grip the tube with Mole Grips
Pull and twist.

To replace with a new tube (you've just destroyed the old one!
Warm the casting locally with a blow lamp.
Lubricate the tube.
Using a drift with a shoulder that fits the tube (or a long bolt that is a good fit) Tap the tube into place.

Check the depth of the tube to set the correct Fill reading - There is a whole discussion about this.