He always tells me with my 4WD Rodeo that "NOOOO, don't go on the beach! Do you have any clue what all that sand does to the car?"
Dang it! I love 4 wheelin.
Actually, with beach sand it's not the silicon particles that do the damage. Those are so fine that they don't do any real damage to the undercarriage, and it's no different than driving on a dirt road. The problem is that beach sand is loaded with SALT. When you drive on a beach the stuff that gets blown up into the nooks and crannies is loaded with salt particles from the ocean spray. It will work it's way back up into frame members and body joints in solid form, then set there awaiting a little moisture. The first time it gets wet (like the next time you drive it in the rain), the salt begins its unstoppable work of corroding the metal around it.
Back in the late 50s/early 60s our family vacationed yearly in Florida, specifically Daytona. My dad drove the family 57 Ford Custom up and down the beach until he found a decent place to perch for the day. Within 3 years the rocker panels rusted through and the frame began corroding badly. In those days corrosion protection consisted only of exterior primer and paint, and otherwise the metal was just bare steel. When my dad complained to the dealer the dealer just asked him if he'd been to Florida with the car -- apparently they saw it enough, even here in Indiana, to know it was a problem.
I also know a guy who had a late-90s Jeep that he had to dump after the frame rusted through from the inside. He had bought it used from somebody in NC who used it along a beach area, and salt/sand worked its way into a boxed frame section. His flirst clue of trouble was when a rust hole appeared on the frame. Inspection revealed the entire thing was corroded from the inside and really in poor shape.
So beach sand is really some pretty corrosive stuff, due to the extremely high proportion of salt in it.
