Possible Door Corrosion

[Cobra Jet]

Sorry to barge in, but you seem to have good knowledge on this topic,
Is this picture an example of a paint pop or extra paint drip that was left and clear coated over? I recently noticed this "pimple" above the 5.0 emblem and it's perfectly circular and hard to the touch. I have no idea how to tell if this is corrosion related or just a paint defect ei. overspray or whatever. I'm sure my dealership would be in the same boat if I can't determine it's corrosion. Any advice or insight on this?

IIRC front fenders are aluminum… that could be the same issue that happens with the hoods. If it’s not aluminum, then it’s an issue with dirt being under the paint and it’s now breaking out…

It doesn’t look like a stone chip, because if it was, it would be below the surface. There would be a physical divot in the surface, breaking clear, color and be down to primer or metal.

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[Albertcado]

IIRC front fenders are aluminum… that could be the same issue that happens with the hoods. If it’s not aluminum, then it’s an issue with dirt being under the paint and it’s now breaking out…

It doesn’t look like a stone chip, because if it was, it would be below the surface. There would be a physical divot in the surface, breaking clear, color and be down to primer or metal.

if it was dirt or something like that breaking out now, can I just leave it and it won't do any more harm?

 

[cmxPPL219]

if it was dirt or something like that breaking out now, can I just leave it and it won't do any more harm?

I had a very similar spot / debris like this, on my passenger side fender, just under the 5.0 emblem.

It turned out to literally be debris (small piece of metal, just about the size as yours in your pic, except with a bit sharper corners). It was not just in the clear coat, it was painted AND cleared over.
I saw it prior to taking delivery, and didn't bother to have the dealer correct, for fears of them making things worse, and now the original panel isn't original paint (as flawed as Flat Rock's factory paint job is anyway lol.)

So long story short, one day, I was washing the car, and finally, my microfiber towel tore it out. So it looked like a tiny scab. In my case, I put touch up paint over it and moved on.

 

[Albertcado]

I had a very similar spot / debris like this, on my passenger side fender, just under the 5.0 emblem.

It turned out to literally be debris (small piece of metal, just about the size as yours in your pic, except with a bit sharper corners). It was not just in the clear coat, it was painted AND cleared over.
I saw it prior to taking delivery, and didn't bother to have the dealer correct, for fears of them making things worse, and now the original panel isn't original paint (as flawed as Flat Rock's factory paint job is anyway lol.)

So long story short, one day, I was washing the car, and finally, my microfiber towel tore it out. So it looked like a tiny scab. In my case, I put touch up paint over it and moved on.

Yea as long as it's not going to affect the rest of the paint or cause further damage I can just move on, it's the uncertainty about it being corrosion which has me worried. It's similar to what you described, but it appeared recently so I I'm hoping it's either dirt, a very tiny rock or debris starting to show since it feels very hard. It feels and looks like the paint and clear is covering over it like yours. I'll just leave it for now and see what it does before I assume it's corrosion related.

 

[cmxPPL219]

Yea as long as it's not going to affect the rest of the paint or cause further damage I can just move on, it's the uncertainty about it being corrosion which has me worried. It's similar to what you described, but it appeared recently so I I'm hoping it's either dirt, a very tiny rock or debris starting to show since it feels very hard. It feels and looks like the paint and clear is covering over it like yours. I'll just leave it for now and see what it does before I assume it's corrosion related.

Yes, reading what you described, my fear also is that in your case, it's corrosion-related, because you said it appeared recently.

As CobraJet mentioned, the fenders are, in fact, aluminum, just like the hood. So that means they're at risk of "galvanic corrosion."

This forum has some threads on it. This is one example I found:
https://www.mustang6g.com/forums/threads/tsb-19-2026-aluminum-panel-corrosion.117031/
You can also search Google for Ford aluminum panel corrosion.

Basically, the overall assumption is that during the manufacturing process of the aluminum panel, a small piece(s) of other metal (non-aluminum) debris make it in and contaminate the panel. Then, it's painted and cleared over. So the problem is, despite efforts to wash, clean, or even rust proof aluminum panels with RustCheck or Krown, it does nothing to stop the aluminum panel from corrosion because it's happening at the panel-level, under the paint.

I have a friend with a 2017 GT and he just had his hood replaced for this reason. (another previous poster in this thread had the same issue). My friend had ti replaced under the corrosion warranty.

Perhaps get yours checked out, but the key thing to mention is that that blister you have on yours appeared out of nowhere, and make it known to the dealer that you're also aware of the TSB that exists for this issue.

 

[Albertcado]

Yes, reading what you described, my fear also is that in your case, it's corrosion-related, because you said it appeared recently.

As CobraJet mentioned, the fenders are, in fact, aluminum, just like the hood. So that means they're at risk of "galvanic corrosion."

This forum has some threads on it. This is one example I found:
https://www.mustang6g.com/forums/threads/tsb-19-2026-aluminum-panel-corrosion.117031/page-2
You can also search Google for Ford aluminum panel corrosion.

Basically, the overall assumption is that during the manufacturing process of the aluminum panel, a small piece(s) of other metal (non-aluminum) debris make it in and contaminate the panel. Then, it's painted and cleared over. So the problem is, despite efforts to wash, clean, or even rust proof aluminum panels with RustCheck or Krown, it does nothing to stop the aluminum panel from corrosion because it's happening at the panel-level, under the paint.

I have a friend with a 2017 GT and he just had his hood replaced for this reason. (another previous poster in this thread had the same issue). My friend had ti replaced under the corrosion warranty.

Perhaps get yours checked out, but the key thing to mention is that that blister you have on yours appeared out of nowhere, and make it known to the dealer that you're also aware of the TSB that exists for this issue.

What's a good way to actually determine if it's corrosion or just a paint defect? At this point now, visually I have no idea. The corrosion bubbles I've seen on other threads are flat and random in shape, clustered together, but the bump on my fender is pointed out and perfectly spherical.

 

[cmxPPL219]

What's a good way to actually determine if it's corrosion or just a paint defect? At this point now, visually I have no idea. The corrosion bubbles I've seen on other threads are flat and random in shape, clustered together, but the bump on my fender is pointed out and perfectly spherical.

You could monitor it for a while and see if it gets slightly worse, but I would personally not do anything to it, since if you do eventually have to go to the dealer to make a claim, they may say that the see evidence of tampering, etc.

But imho, if it just appeared out of nowhere, on an aluminum panel, chances are it's not a paint defect, because those will be there from the factory, new. Anytime that something starts to develop over time, where it's metal/paint-related, it's usually corrosion/rust.

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