Originally Posted by H1Tad

Galvanic corrosion is a thing and its insidious. It is extremely difficult to stop and you won't know its a problem for years. On my big truck, the body is 6061 T6 aluminum but the wagon top is mild steel. The factory installed a 1/4" thick rubber gasket on the mating surface where the two meet however - over the course of 15 to 20 years, most wagon tops are completely rusted away due to water intrusion.

I have a feeling that the L663 will be similarly affected - especially in conditions like where I live where during the winter, there's so much salt on the roads that the pavement turns white (and not from snow) alongside being 300 feet from the Atlantic Ocean.

That being said, I did look under my L663 which has spent its whole life in Massachusetts and Maine with no additional undercoating that I know of - and it looks pretty new. Some surface rust is starting to form on exposed bolt heads but its doing pretty well for a car thats spent 3.5 winters in coastal New England. I think I am going to invest in a undercoating to protect it long term however. My big truck uses NH Oil which is a sticky black oil that goes all over everything and its worked magnificently, but its also a huge mess when you have to work on anything under the truck. Rust-Chek looks a lot more civilized.