Cracked Blocks

[Chris KC]

Apologies if covered before, but many cylinder blocks now have small cracks radiating out from the centre head stud. The general consensus seems to be use another one if you have the choice.

I'm curious, has anyone actually suffered an engine failure as a result of these cracks?
And if yes, what happened? (Water in the bore? Stud pulled out? Or something more dramatic...?)

Anyone found a way to repair them?

Thanks
Chris

I believe these to be heat cracks.If the threads are in good condition just use as is, if the tread is iffy
go to 3/8 BSF and use a stepped stud which gives a much better result than helicoils, Attached are images of 2 blocks with this problem, it is not uncommon.If it was my block I would have the top face skimmed, drill out the water holes to clear them of crud/limescale,remove the coreplugs, and have ii
acid cleaned, or do it yourself with Bilthamber.I would not attempt to have this repaired, it will do more harm than good because there is so little material in the vicinity.
Someone mentioned oil coming up through through the studhole, strange as there is no oil there, the stud goes into the waterways.When refitting the studs I use loctite 242 to seal the threads.
I short Chris I wouldn’t worry about the crack.

Thank you Zete. I would have been interested to see your pics but I don't find them?