Rusty back door

[Nomad]

Hi, I am new to the forum... so forgive any protocol gaffes please? I have a 2011 Expedition max(EL) Limited and I live in Canada.
On the back door, (rear hatch opening door? ) I have had rust bubbling under the paint around the transverse handle and the chrome trim over the licence plate lights. It also seems to be rotting along the inside bottom edge and the rear lower edge of the lift up window opening. The rest of the car is totally rust free so why just this area?
Is this common? I had the thing repainted under warranty but it came back now 3 years later. Is this just poor quality workmanship or a design fault? Is there anything I could have done to prevent this happening? I asked at my local dealer what the cost of a door skin would be... $5000.000!!! For just a skin!! Is Ford building in this issue to sell more parts? Other than OE I am not aware of any aftermarket replacement part ... well, not in Canada... anyone with any suggestions please?

 

[Plati]

It isn't rust. The rear liftgate is aluminum. It's aluminum oxide.
Join the club!!
In a way it IS your fault, you could have bought a TAHOE to avoid this.

https://www.expeditionforum.com/thr...gister-a-complaint-read-fords-response.16012/

 

[Nomad]

Thank you for your reply! So, I was not aware it was not steel... so the corrosion may be due to steel fasteners touching the aluminum panel? It's a shame as the rest of the car is good and it's a great car otherwise... I guess it's either a new lift gate or just watch it rot... Thanks again. Appreciate your time and effort...

 

[Nomad]

Thank you for your reply! So, I was not aware it was not steel... so the corrosion may be due to steel fasteners touching the aluminum panel? It's a shame as the rest of the car is good and it's a great car otherwise... I guess it's either a new lift gate or just watch it rot... Thanks again. Appreciate your time and effort...

 

[Plati]

Thank you for your reply! So, I was not aware it was not steel... so the corrosion may be due to steel fasteners touching the aluminum panel? It's a shame as the rest of the car is good and it's a great car otherwise... I guess it's either a new lift gate or just watch it rot... Thanks again. Appreciate your time and effort...

So … not likely to be galvanic corrosion, if that's what you meant by "steel fasteners". You will find various theories but in my experience it happens UNDER the paint … at locations near edges and bends in the metal. My theory is that "water" (or water plus other chemicals) gets under the paint where it reacts with the aluminum and oxidizes. Its generally kind of harmless but I have seen where it will eventually penetrate the aluminum panel. I sanded the paint off an area on my hood and the corrosion stopped. This is a year and 1/2 old like this.


I think you could sand blast ALL the paint off the liftgate and it would never corrode again plus it would look very cool and only be a blinding reflection hazard to people behind you, but who cares about them anyway (just kidding).