I noticed few smaller rust spots on the inside bottom of the passenger side door. Its just getting to the point where you can barely see if from the outside. i want to prevent this from getting any worse and was wondering what i should do? we wash our cars religously in the winter to avoid rust from salt but i dont want it to get worse this winter. thanks

Time for rust coating. Do you have Krown or Rust Check in the US? Also get the underside oiled for furthur protection. The problem with rust...once its in the metal, there is no stopping the oxidation process. :?

All you can do now is preventative maintenance.

Umm actually that is not entirely true. Many companies make a product called rust converter. Most auto parts stores carry it. You brush it onto the rust and let it dry. It goes right into the rust and converts it into a hard black material. These products work great. I put it on big exterior rust patches on an old car I had once, and the rust never progressed any further, and I didn't even put paint over it. On my bonnie, I have been using it on all rust spots I find underneath the car. I have found that the paint is coming off at all the spot weld joints underneath the car, so I have been scraping them off and treating them. The converter also will stop rust on the metal brake lines, etc. You can follow it up with undercoating or paint if you want to. This product also comes in a small paint chip repair kit that is sold by GM.

It also helps to wash the underside of your car. Whenever I wash the car, I get down on the ground and try to wash off everything under the car. Do the wheelwells, and way up behind the rear bumper, etc. And once in a while I do the engine and everything under the hood. Just don't do it on a hot engine.

Umm actually that is not entirely true. Many companies make a product called rust converter. Most auto parts stores carry it. You brush it onto the rust and let it dry. It goes right into the rust and converts it into a hard black material. These products work great. I put it on big exterior rust patches on an old car I had once, and the rust never progressed any further, and I didn't even put paint over it. On my bonnie, I have been using it on all rust spots I find underneath the car. I have found that the paint is coming off at all the spot weld joints underneath the car, so I have been scraping them off and treating them. The converter also will stop rust on the metal brake lines, etc. You can follow it up with undercoating or paint if you want to. This product also comes in a small paint chip repair kit that is sold by GM.

It also helps to wash the underside of your car. Whenever I wash the car, I get down on the ground and try to wash off everything under the car. Do the wheelwells, and way up behind the rear bumper, etc. And once in a while I do the engine and everything under the hood. Just don't do it on a hot engine.