Hi Tim, an excellent post, thank's for the photos and for all your efforts to unravel the reasons for the failures. There's certainly no doubt in my mind now the underrated heaters are definitely the problem source. The crack location in respect to the hottest part of the electrical heater element is proof enough to me. I'll also mention the element I removed from my fridge also had it's deepest discoloration around the point. It's part # is 173742-28 which is listed as the heater element for a NDR1062, although my fridge is a RM3662.
the failures I've seen, they have almost all been coaches owned by full timers that ran the refer constantly on 120v electric. The average time frame for a failure to occur (on the ones I've seen) is between 2-3 years of using in this manner.
The fact that our RV is in reality a camper van, but has spent 5 years in a busy rental service, the fridge was most likely used on propane for the greatest % of time. This might explain why after seven years it has not failed yet!(fingers crossed on this one :R)
Not that it's important, but if they're mostly interchangeable, and have the same specs I wonder why all the different part numbers.
Cheers Willis
