Looks like the block is cracked - Never, ever buy Dart

[lukep6470]

it does have the plenum. That must be where the hole is as it is the only way all cylinders could get water in them at once. New manifold is already ordered. If it works you can have the old one if you like.

[Shaunp]

What coolant did you have in it.

[nassi]

What coolant did you have in it.

Steam

[Nuts]

Yep!

[lukep6470]

Concentrate with RO water

FOr testing I was just using RO water.

[lukep6470]

Fixed!!!

I don't think intake manifolds are meant to have a tide line in the vacuum plenum:

https://photos.app.goo.gl/wieqsAqHN2oFSd8L7

[hybrid]

What brand is that manifold?

[lukep6470]

It seems to be the standard weber one most of the itb kits come with. I suspect Procomp.

I've replaced it like for like.