Rust on Inner Door Panel

I would open up that door (like when I installed sound deadening material for sound system) to gain a greater scope of damage.
 
Me too. Would've done it before I even made this post...

Its been awhile since that project. If I recall the inside of the actual outer shell of the door is painted with anti-corrosion stuff. Not fully painted. But the section where OP has damage is fully painted at factory. That said, I would resolve the rust issue before it reaches/spreads towards the inner shell.

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As a matter of interest, that big plastic moulding is actually a sealed container and the sensor with the red clip is a pressure switch. If the container gets squashed in a side impact, the increase in pressure activates the switch which is and additional contingency in case there is not enough impact to activate the side impact inertia switches - the airbags still deploy.

I*ve seen owners cut a great hole in it to add bigger speakers...... oh dear!
 
As a matter of interest, that big plastic moulding is actually a sealed container and the sensor with the red clip is a pressure switch. If the container gets squashed in a side impact, the increase in pressure activates the switch which is and additional contingency in case there is not enough impact to activate the side impact inertia switches - the airbags still deploy.

I*ve seen owners cut a great hole in it to add bigger speakers...... oh dear!

Oh yeah I didn't cut nor alter that black sealed container thingy. I also added secondary weather stripping and that door feels, knocks, taps, and closes like a Benz :)...okay maybe more like a BMW.

OP may access this panel himself with basic tools and plastic trim removal tools from Harbor Freight.
 
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There is misinformation in the thread now.

Save the photo and have a proper look at it. Why would the sealer be scraped off when new and then left that way? The repair has been primed and quite badly too. You can see wire brush marks in it.

Leave the owner thinking his paint has peeled off under the door seal for no apparent reason if you think it will make him feel better, it doesn*t really matter to me.

It looks like the seam sealer was scrapped off... which is what the OP said they did.
 
There is definitely some misinformation in this thread. The door looked like any other door does PRIOR to me uploading the picture. When I was drying the car I noticed the paint was bubbling adjacent to where the seam sealer is. When I pushed on the seam sealer I could see it was cracked and water was being pushed out from in behind the seam sealer when I pushed on the seam. As I mentioned in my original post, I started scraping the seam sealer and paint off to see the scope of the rust and the total affected area. Once I did that I took the photo. So, what you're seeing in the photo is after I removed the paint and seam sealer with a small flat headed screwdriver. Prior to that photo you would have seen an intact door with very minor bubbling of the red paint adjacent to the seam sealer.

I have taken the vehicle to two independent body shops (one national chain and a small shop). Both have concluded that the door has never been repaired before and that moisture found its way behind the seam sealer and started the corrosion. Its currently in the shop being repaired.

The purpose of the post was an FYI for everyone else who owns a similar model year to keep an eye out for corrosion along the door seams. While the vast majority of the CX-5s out there are likely fine, there was obviously an issue from the factory with mine.
 
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I'd have this covered under the bumper-to-bumper warranty through Mazda USA. I would argue that the damage was from the factory and caused rust problems while within warranty period. I would also proceed to identify similar bubbling all around the vehicle just in case.
 
There is definitely some misinformation in this thread. The door looked like any other door does PRIOR to me uploading the picture. When I was drying the car I noticed the paint was bubbling adjacent to where the seam sealer is. When I pushed on the seam sealer I could see it was cracked and water was being pushed out from in behind the seam sealer when I pushed on the seam. As I mentioned in my original post, I started scraping the seam sealer and paint off to see the scope of the rust and the total affected area. Once I did that I took the photo. So, what you're seeing in the photo is after I removed the paint and seam sealer with a small flat headed screwdriver. Prior to that photo you would have seen an intact door with very minor bubbling of the red paint adjacent to the seam sealer.

I have taken the vehicle to two independent body shops (one national chain and a small shop). Both have concluded that the door has never been repaired before and that moisture found its way behind the seam sealer and started the corrosion. Its currently in the shop being repaired.

The purpose of the post was an FYI for everyone else who owns a similar model year to keep an eye out for corrosion along the door seams. While the vast majority of the CX-5s out there are likely fine, there was obviously an issue from the factory with mine.

You may want to have the Body Shop look at whether any of the door drains on the bottom of the door and/or weather seals at the top of the door are compromised or damaged.
 
How many kms and which model year and when was it built and when you bought would be helpful.
 
Joe, did you take it to a Mazda dealer and show it to them? A visual inspection. And they said the warranty doesn't cover it unless it's perforated??

If so, that blows my mind.
 
Joe, did you take it to a Mazda dealer and show it to them? A visual inspection. And they said the warranty doesn't cover it unless it's perforated??

If so, that blows my mind.

Most car manufacturers only cover "rust perforation" which essentially means the vehicle needs to rust through the metal completely.
 
Most car manufacturers only cover "rust perforation" which essentially means the vehicle needs to rust through the metal completely.

Precisely. Read the corrosion warranty. It covers perforation (a hole) only. I did not take it to the dealer because I knew they wouldn*t cover it under warranty.

The vehicle is in my signature. It has 266,000km/166,000 miles, but as previously stated has been oil sprayed annually and has been very well taken care of. Vehicle was built in April of 2014.
 
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You may want to have the Body Shop look at whether any of the door drains on the bottom of the door and/or weather seals at the top of the door are compromised or damaged.

The seals are all good and the drain holes are clear. The door seals wouldn*t do much to prevent this type of corrosion due to where they*re located (seals are inboard of affected area). The inside of the door panel has a film of rust proofing which is supposed to keep out moisture and prevent corrosion. From what I have been told, the issue seems to be a compromise in the seam sealer where the door seam *kicks out*.
 
Precisely. Read the corrosion warranty. It covers perforation (a hole) only. I did not take it to the dealer because I knew they wouldn*t cover it under warranty.

The vehicle is in my signature. It has 266,000km/166,000 miles, but as previously stated has been oil sprayed annually and has been very well taken care of. Vehicle was built in April of 2014.

Understood. Given the location, a good argument might be made for an exception. But I also understand not wanting to even bother talking to the dealer.

What's the repair going to cost you?
 
That*s just it. It*s not worth it to me to argue with them. It sucks, but I assume it*s a fluke issue. They have to remove the rust and see if it wraps around the front under the moulding. If it*s localized it will be $300 to remove the rust, epoxy and refinish. The price goes up if they have to paint and blend the front side of the door.
 
I have a 2018 and the rear doors drain poorly. My rear doors may rust over time like yours if i'm not diligent to open the doors to let the water run out after a wash or pouring rain.
 
I have a 2018 and the rear doors drain poorly. My rear doors may rust over time like yours if i'm not diligent to open the doors to let the water run out after a wash or pouring rain.

Normally *rust proofing* a vehicle would prevent that type of corrosion because a fine petroleum based mist is sprayed in all body panels in the hollow, which prevents moisture from sitting in all of the crevices.

I do believe the corrosion on my car started between the seam sealer and the metal as opposed to starting inside the door panel where the two skins are pinched and welded. Unfortunately, the rust proofing I*m suggesting for your vehicle wouldn*t have helped in my case.
 
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