[81MC]

The internal rust protection (Ziebart, Waxoil, Cavity wax), whatever they call it, is a very good idea. As in, I tell literally anyone who will listen to either do it themselves, or have a professional so it.

It’s not often that rusty vehicles started rusting from the exposed surfaces fist; it’s almost always creeping from seems and through panels. A diligently applied cavity wax provides a physical barrier to prevent this, with capillary action to reach the tightest of seams and crevasses.

All those GMs with rotted out box sides? Had they had a proper cavity wax from new, they likely would be quite presentable, not garbage 10 years later. Same thing with those Mercedes front fender rot, Audi lower doors, those civic dog legs etc.

Efficacy? - nearly every OEM requires the application of cavity wax during the collision repair process.

We would hope and expect that the factory has applied all the necessary coatings from the factory, and maybe if your car saw clean roads and sun year round it would be enough. Fact is you won’t know until it’s too late, and we have every possible hazard for sheet metal in our climate.

I’m not sure I would trust the dealership lackey to do a full and complete job, can’t say. But seriously find a shop who knows the value in it and have it done. It’s not often that the cheapest method is the best, but this is one of the rare cases.