The 'yellowish/green' residue is NOT ammonia..ammonia turns to vapor and dissipates fairly quickly
The sodium chromate is the residue left behind when cooling unit leaks
Sodium chromate is an anti-rust inhibitor and is what crystallizes when overheated.
Crystals form and plate out on inside of tube
When cooling unit has a crack (typically in perk tube---boiler) the sodium chromate dries out and leaves the residue behind \ clear tell-tale that cooling unit is no good
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31