You can see the leaking areas in this short video on the left side of the connection, revealed by the bubbles (I had sprayed it with soapy water for greater visibility).
URL (needed for some mobile devices): https://youtu.be/Eq-lkah6yXY
Alternate URL: https://www.youtube.com/watch?v=Eq-lkah6yXY&feature=youtu.be
|Heavy corrosion was visible, including exfoliation of the metal beneath the surface coating (paint).|
|Tap to expand for greater clarity.|
Manchester Tank's customer service was extremely helpful and quickly emailed me their drawings for both the original #68162 and the potential replacement #6813 that I had identified (if anyone needs those PDFs, contact me via interstate.blog -at- gmail). Armed with those drawings, I was able to go to my local RV repair center and ask them whether they could detect any engineering differences that would disqualify the #6813 as a substitute. This initial part of the process is often more expensive and time-consuming - a non-DIYer owner would take their RV into a service center and let them determine what the replacement ought to be. But that involves an extra trip plus labor charges for an initial examination of the rig and the corresponding research on their parts. I was motivated to minimize costs for this repair, so I did that legwork myself.
Drawings laid side by side on the service counter, nobody could see any reason why the substitution could not be made, so they ordered the tank and a few days later my service appointment was scheduled.
|The installation did not go as easily as I'd hoped, for the reasons described below.|
Such was the case with this tank replacement. Out of necessity, Airstream apparently installed the original LP tank in a rather unconventional, reverse-logic manner. There's a tank, a mounting bracket, and a chassis, right? So according to common expectation or paradigm, one would expect the installer to put the bracket on the chassis and then mount the tank on the bracket. But because the work space was so incredibly restricted, what Airstream appears to have done instead is to put the tank on the bracket, cut the bolts flush, and then weld the bolts onto the bracket. They then lifted lock, stock, and barrel up to the chassis and secured it from inside the Interstate, through the floor. That was effective, but it wasn't intuitive, and a lot of labor was needed just to figure out how to dismount the welded-on original tank from the chassis.
|It actually does, but it wasn't immediately apparent.|
Alas, that efficiency was not to be, because of the welding that had been done, and because it took the service facility extra time and effort to determine that the only way to dismount the original tank was to jack up the fresh water tank inside the Interstate, and locate the LP bracket bolts beneath it. Who knew?? It would have taken me forever to figure this out.
So for those of you facing this same situation, those are important pointers for your repair facility. Don't let them re-invent this expensive wheel. My total cost was about $550 for the tank and $720 for the labor.
Here are a few shots of the new tank as installed.
|Forward end. The orange thing at photo bottom behind the tank is the running board ("ground effects") on the starboard side of the vehicle.|
I don't know why the original LP tank rusted out so badly and in such a short period of time. I have the original purchase and maintenance records for this Interstate, and there was nothing in that documentation, nor was there any physical evidence, that this vehicle was subjected to unusual operating conditions. It was reportedly bought by a newly-retired gentleman and his wife in the Midwest and kept primarily in the Midwest. It was driven only lightly, an average of about 3,500 miles per year.
This kind of premature rust is a potentially treacherous problem for RV owners because it is so unexpected that they might not think to check for it. I have extended family members who have house-servicing propane tanks in their back yards that have been directly exposed to the elements for decades and still show only the barest surficial corrosion, certainly nothing structural and certainly nothing that would cause leaks. I myself own a portable BBQ tank which is spotless after a lifetime of sitting outside in full subtropical weather exposure.
|I can't even remember how old this thing is, or how many years it has been sitting outside, and look at it. It's still in perfect condition.|
I don't have an answer for this one. All I know is that propane leaks will not improve on their own - they will only get worse, and they could do so with catastrophic consequences. So this is something for which every RV owner should remain on the lookout.
Further discussion and commentary can be found on this Air Forums thread.