White scale on fuel injector

[CRSWA]

Found a white chalky scale on #4 fuel injector. Speculation on what this is caused by?

(2L-TE, updated head, 100k miles, vibration at idle, power is okay)

 

[OTBT]

Water ?

 

[CRSWA]

Water ?

Yeah, that’s the nightmare scenario, but if the head were cracked, I’d see evidence of it in the coolant, right?