Stephen,
You're not worrying about nothing - your trying to protect the investment of time and materials.
However...
There should be no problem with corrosion - most 'foil' insulations have a plastic coating and even where there would be direct metal to metal contact the corrosion process is so slow that you won't see any problems in your life time. I would imagine the engine of the Kia van will expire long before corrosion sets in.
If however you were immersing the van in sea water you may have a bigger corrosion problem, but then you'd have a boat
VAZ