From what I can tell, nothing was sprayed on this coil. The copper suction line leaving the aluminum header was completely corroded. These craters became pin holes over night. It drained the system in less than 24 hours. Most likely the cause is cheap materials. Of course the new one seemed to be made out of the same quality material. That’s Carrier for you. Coil came with no drain pan, no txv and a $1600 price tag at dealer cost.