Rear Doors Rust, Bottom / Interior

[oskar27]

I have a 2016 Edge Titanium, FWD, 2L ECOBoost, 62K Kilometers no problems so far at all. Leased the car new and bought the lease at the end. I'm aware of the coolant intrusion issue.

 

The interior of both rear doors by the bottom started rusting. That's a bad doors design because the way the doors are made it creates a place for dirt to accumulate in that area and start rusting.

 

Plan to go to a body shop soon. The two front doors in the same area are clean but depending on how they will fix the rear doors I may ask to do the same on the front doors.

 

Any idea how they can fix the problem?

 

Thanks

[enigma-2]

On 3/20/2026 at 7:40 AM, oskar27 said:

.... Any idea how they can fix the problem?

 

[oskar27]

Thanks for the tip enigma-2

[Samurai Edge]

The only problem with the video above is that you are now spraying over the rust that is already there.  The best time to do that is when you first buy your brand new car.

[oskar27]

Good point mate but I thought he sprays the inside of the cavity at both ends? 

Anyway tomorrow I go for an oil change and will see what the dealer has to offer

Thanks

[Samurai Edge]

Doesn't matter which end he sprays in.  If you see rust, then you have rust, plain and simple.  You will not know how much rust you have in that door unless you take the door apart.

 

Covering the rust with any type of lubricant / sealer / anti-rust compound does not make the rust go away.  It masks it.

The only real way to eliminate the rust is to cut it out and you will have to take a good section of the rusted area and the surrounding non-rusted area out to ensure you get it all, or as much as possible.

 

Rust is a cancer.  What you don't see is what can kill your car.

[oskar27]

11 minutes ago, Samurai Edge said:

Doesn't matter which end he sprays in.  If you see rust, then you have rust, plain and simple.  You will not know how much rust you have in that door unless you take the door apart.

 

Covering the rust with any type of lubricant / sealer / anti-rust compound does not make the rust go away.  It masks it.

The only real way to eliminate the rust is to cut it out and you will have to take a good section of the rusted area and the surrounding non-rusted area out to ensure you get it all, or as much as possible.

 

Rust is a cancer.  What you don't see is what can kill your car.

I understand all this and what rust can do and I do not want to cover the rust. That area at the bottom of the door is very difficult to cut and re build and that's the reason I posted here to get info from other members. Hopefully the dealer tomorrow will tell me how it can be fixed.

Thanks

[enigma-2]

The spray converts the rust into a stable compound and stops future rust. Been out for years. 

 

"Fluid film" can also stop rust in its tracks. 

[Samurai Edge]

Years ago, back in the 80s, I used a product ( name forgotten ), that made that same claim and actually worked.  Within the last 10 years somewhere, no longer, I used the same product again and it did nothing.  The company obviously changed the formula, as is so common anymore, to save money.

 

The product was definitely not " Fluid Film ".  If " Fluid Film " really works, that would be great.

[enigma-2]

Probably POR-15. It's messy, but it works. Other products include  Corroseal, Rust-Oleum Rust Reformer and Mar-Hyde One-Step. They are advertised to convert iron oxide (rust) into iron tannate (a paintable black layer. 

 

Fluid Film is lanolin-based. It blocks the air from reaching the existing rust and prevents it from growing. 

 

Don't know what your dealer would use, if I would do myself, id use Rust-Oleum Rust Reformer, mainly because it's easier to spray inside th÷ door drain holes.

 

.

Edited Wednesday at 07:36 PM by enigma-2

[enigma-2]

<Oskar27> like to know what your dealer did/said. They spray or tear the door apart$$?

[oskar27]

The dealer does not do body work (as I suspected) but he gave me the address of a body shop they use as needed. I will go to this shop next week some time and post back. Body shops are "tricky" business so I would rather go to one it's recommended by the dealer.

My thanks to all

[enigma-2]

You'll probably be better off. 😁

 

Keep us informed as to what happens. 

 

 

.

Edited yesterday at 06:19 PM by enigma-2

[oskar27]

Body shop is out of my way and with the Spring freezing rains we have makes it more difficult. Will try next week.

[Samurai Edge]

On 3/25/2026 at 3:31 PM, enigma-2 said:

Don't know what your dealer would use, if I would do myself, id use Rust-Oleum Rust Reformer, mainly because it's easier to spray inside the door drain holes.

 

 

I'm fairly certain that Rust-Oleum Rust Reformer is the product I used years ago.  I would not use it now as  the product became ineffective.

 

I've never used POR-15 nor Fluid Film.  Everything I have read about the two products has shown that:

     1.  Fluid Film works, but washes off and needs to be re-done once a year, at a minimum.  All depends on your operating environment.

     2.  POR-15 works very well, but as stated, it's messy and, IIRC, professional equipment is needed to apply properly.  You don't just spray it on.