You can't seriously believe that rain does not get inside the door & go
down to the seam, & out the drains..

I'd still be painting the insides, if I had the problem...

 

I was told that unfolding the seam would require replacing the outer door skin, so I might as well get a whole new door. I think that is the next course of action if I have to bring it in again.

 

That is what they do and that is what it needs done.

 

That is what it is designed to do. That is what all cars do. The metal is treated and this is what prevents the rust.

The issue here is on the out side in the seam.

Generally all car doors are protected with treatments and coating. This is why they have drains in doors and fenders.

In fact even when it rains now I get some of the inter coating leaving a stain on my rockers where it drains out. They usally have a waxy like coating on the treated steal.

The metal on a car is dipped, treated and coated pretty well. The issues here is some of that coating is getting knocked off in the seam when it is folded and sealed.

Painting the inside will not hurt but really is not needed.

In the end they all will rust our from the under side anyway in 10 years in most parts of the country.

 

Exactly but they will cover some rusted seems on doors. It depends on the GM warrenty rep and how well your dealership works with them.

The front doors have 4 drain holes in them and the rear doors have 3. That is pretty good.

That all being said... Mine goes into the dealership to get rust proofed next week. They will spray this rustproofing that looks like thinner petro jelly in all the doors thru those door drain holes in all the doors, the hatch and the seems under the hood. Then instead of using that on the under carriage where it can be seen. We are spraying the underbody with the black sound deadening spray that we already have in our wheel wells. But this will cover the entire bottom of the car. Certainly a slight PIA when it comes to do suspension work but well worth it in the long run. Can even get a can of it for touch ups later. It will not only seal/rust proof it, but also cut down on more road noise. WIN WIN

best part is, being done at a dealer so it extends and broadens my rust protection with GM. Further, done for cheaper than you think.

 

Yeah, my dad and I sprayed a can of rust proofing up each drain hole in the doors, hatch and hood. Hopefully that should help out. Normally we spray oil up the holes on our cars each fall, but with the rustproofing we shouldn't really need it. It's a spray can that is a liquid, then hardens up after a little bit leaving a hard layer of it over everything it touched...so it should get into each crack and crevice.

 

Sounds like you're doing the right thing.
Being a bit older than you and living in the same area, I remember two different methods of rust proofing that actually work. One was a friend who sprayed everywhere and everything on his 1975 Datsun truck with waste oil every two years and then pulled it into a field to drip dry on a hot summer day. These trucks rusted badly in our weather although his did not have one rust through spot on the truck twenty years after it was made.

The other is a place up in Midland, MI called Henderson Bros. who have done rust proofing for a long time. Their reputation is great and I've never seen a vehicle they did with rust thru. I've seen vehicles after they've done them and it looks like thick oil which drys to the touch on surface although stays gummy underneath. It must be really thin when it's sprayed on as you can see where it's run out of drains and along body seams. Not sure what they charge nowadays although seems like just shooting the doors would not be too cost prohibitive. Might be worth a try, especially on a new vehicle to avoid doing the ole disassemble, clean & paint procedure. I'm still trying to do a deal on 2010 HHR and will look them up if I find what I'm looking for.

Motoretro

 

I used to do the "used oil trick" inside the body panels back in the 70's....... EPA would shoot you now though.

Somewhere I thought I read that GM will deny rust claims if any aftermarket rust proofing is done, not sure if it's true or not.

So far my '07 isn't showing anything, I think it is an issue with the glue/sealant in that seam myself... some cars got it proper and some got partial application and it wasn't caught during prep and paint..... I've seen CrazyCarKid's at a G2G, Definitely rust bubbles under the paint at the seam...... did you look at mine Eric? I don't recall.... I know we talked about it some. All 4 doors on mine look like new.

 

Yeah, you showed me the door lips on yours, and they look brand new!

That place in Midland may be worth me checking out.... Only about 25-30 miles north of here....

 

The wonders of living in LA. Rust is just not an issue, and since I originally lived in Michigan, I'm well aware of the rust belt issues.