D7 17A water leak from head studs

Hi all,

We had a 17 A block fitted with a "Z" sleeve on number 4 cylinder as it was cracked beyond shimming.
While the engine is running there are water droplets coming out around the 2 5/8 heads studs just in front of the pre combustion chamber. Apparently when they fit these sleeves the bottom of the sleeve doesn't make contact with the block and a sealant is used to fill the void. I was advised to coat the 5/8 studs with a silicon sealant also to make sure it seals as the insert cuts into the stud holes.
Has anyone had any experience with this type of repair or complications with using it.

The next step would be to pull the head and take out the studs and reseal the threads and the hole with more sealant and try again. Last resort is replace the block. Not looking forward to that scenario.

Cheers djcat