Rust proofing
 

How many of you 911 owners rustproof your cars at a local rust check or krown centres ?

I would be very surprised if there is anything like "rust proofing". The bad rust that causes severe structural damage comes from inside of all the hidden body cavities. Water, salty or not, can get in there but cannot dry out. No "rust proofing" process, that I know of, can insure no rust inside the cavities, especially on used cars.

Here in canada we have krown centres they use a oil to get it in everywhere also into your doors engine bay etc it drips for about 4 days

I use CorrosionX on the underbody and critical fasteners of my C4; usually retouching 1-2x year, especially during the fall (=winter prep).

The thing that's good about CorrosionX is that it creeps out across the metallic surfaces to which it's applied, so you don't have to be ultra accurate in your application. I often use an acid brush to dab it on. It will attract dirt, so it's not great if having stuff stay clean is important to you, but it does stop corrosion very well.

I've got an '04 CRV and my girlie has an '05 Element (same powertrain); her engine bay fasteners and bracketry are visibly quite rusty vs. mine which are dirty but not at all rusty.

$0.02
pd

I've always done all my cars every year I'm thinking the porsche is next

We used to do a very cheap and reasonably efficient method in Germany in the 60's: Before every winter get to a gas station with a lift that does oil changes. There we had them spray used motor oil all over the underside of a car. Then we drove the car for a while over a dry and dusty dirt road. That created a rather thick layer of oil drenched dirt all over. A pretty effective way to protect the under carriage from a winter's worth of rain, mush and road salt.

That's why my 68 bus transmission looks like it was made by clay people!

If you go the Krown route, better check to see if they punch 3/8" holes in rockers doors etc before they start the job. Some do and some don't. I have seen people with brand new cars pretty upset with the holes. Sure Krown installs plastic plugs in the holes but rust will start at the bare metal edges of every hole. Save that car for summer only and no worries.