Dill and Tap intake manifold

[Mr Nick]

I need to drill and tap a new hole in the front coolant passage of my intake. I'm hooking up '4-corner cooling' and need room for my temp gauge sensor and SPAL fan sensor.

My question is, can I simply drill and tap the intake coolant passage? All of the other holes have a raised area around them, which I assume is to allow more thread engagement...?

https://static1.pt-content.com/images/pt/2007/12/edl7111-1.jpg

[RBARNES496]

You have to measure the thickness of the wall. I believe the rule of thumb is 1 1/2x bolt diameter for proper thread engagement.

[CarlC]

I would suggest welding in a bung. The runner is too thin.

[chicane67]

...Or put it in the tank on the radiator.