Wonder if its possible to change piston without removing the engine. It should be plausible, but not sure if its worth it.

I’ve done it on a 2.7.

Difficulty is getting the upper sump out past the steering rack and up past the radiator.

Had to drop the diff on a 3.0 to get the pan out. Not terrible, not easy. 2011 RRS HSE Luxury 3.0 TDV6 Fuji White on Ebony/Ivory
Born and raised in So Cal. Moved to the UK in 2018 for a few years. Now in Poland and looking at moving back to the UK.

Ok, good to know it's possible to do.

I can lift the body off and take the engine out, but it feels like too much work for just one cracked piston.

What would you choose to do if you will have to do it all over?

Not too hard to take the steering rack off ...6 bolts.
Head off Sump off .If you can get to the offending cylinders big end bolts then it all comes out with the piston Always listen to old people or when they die you will live on in ignorance.
The avatar is a picture of the man with a big cock.
Learned to 4x4 on 100 mile beach and Frazer Island QLD
Dont spend money on old cars you will never get it back

I assume you have the head off already?

Or which side is cracked ? One with fuel pump drive ?

We had a 3.0 SDV6 in with a blown up motor due to some clown not tightening the crankshaft timing pulley correctly on his recently replaced engine. It wasn’t too much effort to get one of the heads off. We then had to pull the axles and drop the front diff to get the pan out. Nowhere near as bad as getting in to a 3.6 TDV8. 2011 RRS HSE Luxury 3.0 TDV6 Fuji White on Ebony/Ivory
Born and raised in So Cal. Moved to the UK in 2018 for a few years. Now in Poland and looking at moving back to the UK.