If it leaks, you'll need to tap or helicoil the bolt hole.
Sounds like it has stripped threads.
You're fortunate it's holding it in tight enough.

 

Don’t scare me like this... Let’s all say a prayer.

 

If it does, it's actually a simple repair, nothing to be overly concerned about.
Cross that bridge if you come to it.

 

edit: solved - bolt is M8 x 1.25

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Does anyone know the size of the bolt that holds the heater pipe into the intake?
finishing a head gasket job and I don't know where I put it. Don't really have bolts lying around to test it either. Thanks