I spent the afternoon removing the rear wheel tub liners on my 2017 Ram 1500 to rustproof it, & discovered why these things rust out at the top of the wheel openings! First off, it's doublewall along the top 50% of the wheel tub where it meets the outer bed skin - which I already knew & was expecting. The thing I was not expecting was Dodge's use of soft, black FOAM SEALANT along the whole area where the two come together! So, there is no way to penetrate this tight doublewall area, & the foam of course traps & holds moisture - just like it does on Challengers & I'm sure many other Mopar vehicles. To say I was totally pi$$ed to find this out after all the work is an understatement. I bought this truck back in March with the intent to keep it for at least 10 years. Looks like it's going to rust out prematurely like all the other 2003 & newer Rams - this should happen in about 4 years or so. At least they all do in the rust belt anyway.

I fully intended to apply my magic Texaco rustproofing formula & I also had a spray penetrant anti-corrosion formula. I ended up spraying the non-Texaco stuff as best I could up in the tight areas of the foam-laden doublewall areas - hoping it might creep into & under the foam, but I won't hold my breath. Anyway, thanks Chrysler for building-in rust guaranteed areas!