I believe that was more of a problem with earlier cars than today. For most purposes, the factory treatment is adequate...anything else performed is more like "snake oil" and in some cases can void the original manufacturer's warranty.

Also, some shops in the process of rustproofing you car inadvertently plug up the factory drain holes located throughout the car. So in those situations, water (and salt) is allowed to settle in crevices that would normally be expelled through the drain holes. So it could do more harm than good!

I haven't seen rust on ANY vehicle I've owned after the 70's...and I lived in the snowy midwest, where salt treatment was the norm.

Regular rinsing of the dirt and salt should be sufficient...and cheaper!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car