Water Heater Smell

We’ve got a musty/moldy smell emanating from under the sink shortly after I fire up the water heater. It’s the SW6DE. I’m running on gas only. The smell is NOT in the water. It is NOT the sulfur smell from the anode rod! It really appears to be in the foam insulation around the tank. I pulled a small chunk of foam loose and stuck under my DWs nose. “Yep, that’s it!” The tank also appears to have rust blotches around the inlet/outlet areas. I suspected a condensation problem, since there are no signs of any obvious leaks at all. DW called Suburban this AM and got right through to a tech, who was really helpful! He said the Sub heaters generally don’t have condensation problems and he bet that it has a tiny, miniscule leak and the foam has trapped the water causing the rust/mold problem. He suggested pulling the unit, removing the foam jacket and pressurizing it to inspect for leaks. The smell is bad enough that I’m gonna do something. Has anyone had this or even heard of this problem before? Looks like a fairly straight-forward removal job and will pull it out to inspect this week. If it’s a leakin, I’ll get a new one on order asap. No warranty on this. If it isn’t leaking, I guess I’ll clean off the rust and paint with a rust conversion paint then re-wrap with some fiberglass insulation. The heater works great otherwise.

We’re well on our way to making this “new to us” ’04 2720 ours. 2 and a half camping trips so far and we’re really enjoying it. Perfect fit for our family of four and lab. The front bunk is a great day-time storage area for our instruments and my upright bass even fits inside! Heck even another TM sighting in Newton, IA! The mods/maintenance are adding up to more and more comfort/convenience/safety: Water system accumulator, seam/window re-caulk, brake adjustment/bearing lube, hangar brackets everywhere, sofa support re-enforcement, blue-tote stow, Stereo, XM audio/weather, Travasaks all around, 3 new cooper tires (yes I balanced them!), on-frame levels, cabinet organizers, A/C sound reduction mod, water heater flush/anode replacement, soon PD9260 upgrade, mudflaps, etc... Hey that Dollar General Totally Awesome cleaner works, well, Awesome! Our TM forum membership is the best $12 I’ve spent on our TM, Thanks!
Troy