I had a Ford Explorer in the early 2000's, it was 3 years old when I got it with very low miles (it had been the managers company car). However, looking underneath the car you could see a lot of surface rust and they did have a history of being a bit of a rot box. A bit of homework and we booked in at 'Before & after' down at Newbury (now at Rugby) to get the car treated. Now this would have been 2004 and it cost £550 then - a lot of money. But, he did EVERYTHING and not just spray what you could see but really get into the deep recess' of the chassis, into the doors, the hatch etc. We got a courtesy car and had a bit of an explore of the area and stayed in a lovely hotel for a couple of nights. The car was ready on time and appart from smelling strongly of Waxoyl for a couple of weeks, it was as if nothing had changed. My first MOT after that was an eye opener, the tester said you've got to see this and lifted the car on the ramps. It was just like it had been done yesterday, still shiny and black underneath with not a trace of rust anywhere. I had the car for just under 4 years and it still looked like new when I sold it. Yes, it was a lot of money but it did help to look after my Explorer and it never needed any rust repairs or welding, which was very common when they got to as little as 5 years old. Not Fords best build quality, but fun to drive with a 4.0L V6 petrol engine!