I have it too and in the same location. I think its some kind of glue. Thats what i'll keep telling myself anyway

 

I just picked my car up two weeks ago, was built 6/9 and I have that little "defect" in the trunk just like the pics of the grey one. Don't know what it is but I'm not going to worry about it since it seems common.

 

No issues on my trunk (had similar looking things on my 07 on just about every seam) but my 2012 GT has a paint bubble under the lip of the hood. Going to have it looked at tomorrow, though like an above poster said I will not allow them to repaint my brand new car, I will be stressing that they only repair the paint bubble.

I'm no expert but I don't think its glue, rather deposits. in my opinion the real problem is when you have a pin hole in these "bubbles" that would allow air/oxidization or water and other contaminants to get in there under the clear coat and start degrading the rest of the paint. Rust is such a PITA as once it starts it will slowly eat the rest of the paint.

 

Just a couple of days ago, I have found a bubble about this size (o) just at the edge of the driver door of my 2011 GT. When I tried to polish it away the paint came off and I could see the primer underneath. Unfortunately I cannot go to any local Ford dealer for warranty issues because I live in Switzerland where Mustangs are not imported officially (I bought mine from a import dealer who makes a hell of a living by selling imported Mustang GT's for over 45k Swiss Francs which is about 55k USD...).
Which leads me to my question: does Ford Mexico build their own Mustangs and if yes, are these cars known for quality issues of whatever kind or lower quality in general compared to US built Mustangs? The reason why I'm asking is that my Swiss dealer claims that all of his Mustangs are canadian ones. However all the manuals I got are in spanish and the extinguisher that came with the car is made in Mexico...

 

Tigershark all Mustangs are made in only one plant. AAI (Auto Alliance International) In Flat Rock Michigan. The days of multiple plants making Mustangs are long gone. From 1964 to 2004 they were produce in the Dearborn Assembly plant, Original home for the Mustang. When they changed to the S197 they moved to Flat Rock. In its hey day the Mustang was produced in three plants Dearborn MI, Edison NJ, and San Jose, CA. The Mustang has never been produced outside the U.S. Although it was exported to Germany in the 60's as the T5.

 

The trunk of my sterling grey metallic 2011 GT looks pretty much the same as Norberd's but I don't worry about that since it seems to be "standard".
However, I am a bit worried about the fact that the inside of my trunk not only looks as if Ford did run out of paint but underneath the actual sterling grey coating you can see some kind of yellowish colour (it looks a bit like honey). Is that the primer or is my all new Mustang allready rusting away?

 

You may have a Mustang that has been imported from Canada, but the car was manufactured in the U.S. While stationed in Germany, in '79, my 5.0 needed a belt tensioner. The part was ordered from Canada, by the Ford dealer in Frankfurt.

As for the rust issue, here is a product, POR15, that may help you. I first saw this used on the Chrysler Crossfires, which were made in Germany, on the Mercedes SLK frame, by Karmann. The bottoms of both doors were found to be rusting under the rubber seal. This product will stop and neutralize the rust. You do have to sand away the rust you can see, apply the POR-15, and then paint over it with touch up paint. Works well for inside seams. I have not seen it used on the outside of a door. Hope this is a help to you.

Here is a link;

http://www.por15.com/

I am looking at two spots, one under the hood and one on the inside of the trunk lid. So far nothing has changed since I purchased the car, so I am not doing anything right now.

 

Ford just stripped and repainted the hood on my 2007 Mustang GT with 63K miles on it, the underside and the outer front lip was bubbling up and spreading, had to pay half of the total repair with Ford covering the other half...you just have to ***** and complain to get it done.

 

That would be some form of epoxy.

 

It looks like honey in colour only, not in substance so it must be either a kind of coating or they have really painted the bare sheet metal without even polishing away the rust film covering it all over.

 

All the mustangs have that. you will see that in other parts of the car as well. that is their base coat color (I think it's a rustproofing). you should see that goldish color underneath the car as well.

 

Then I'm relieved! I dig my Pony and don't want it to rust away!

 

...but now I have found a thin rust strip on the inside of the trunk lid where it touches the rubber lip that seals it when closed! According to my local Mustang specialist it's the lip's vibration that slowly rubs the paint away...Not to dramatic but it has to be fixed.

 

...see pic (the yellow line indicates the rust strip while the arrows refer to the rubber lip)

 

Post *****....

 

My 2010 GT had the same color .. mostly around the wheel well , and brakes ,

 

Just got my '12 GT on Thursday, 9/1, and noticed a similar problem on the under edge of my hood toward the front.

I was told that the problem was not rust but was a sloppy weld.

I did find similar areas on the under side of the trunk lid along with an area that was actually scratched down to the metal.

Notified the dealer two hours after taking delivery after finding the trunk lid damage.

If it's just cosmetic, don't know if I want them grinding on the original finish.

Opinions? Thanks!

 

Is it where the trunk touches the rubber lip (see pic above)?