I hope it's not a fake information. Maybe it's possible to reach it with something like that https://www.amazon.de/Proxxon-23068-Micro-Combispeeder-Satz-Gelenk-7-teilig/dp/B000S8B4GI/ref=asc_df_B000S8B4GI/?tag=googshopde-21&linkCode=df0&hvadid=231986057688&hvpos=&hvnetw=g&hvrand=17122699830201545132 ...

Thank you very much. It's a bolt next to the water and oil pump. It's hidden behind a plastic part.

I know but the question is how?

I know it's a pretty old topic, but I have the same issue with my v70 2001 2.4 170hp non turbo. The piston cooling valve screw is leaking.
I wonder how it is possible to remove the piston cooling valve without removing the timing belt and the other stuff? Is it possible?