This is where your Mirage is going to rust out. (Body/chassis corrosion)

[MetroMPG]

Removing the hitch that came with my car, I discovered the boxed "frame rails" at the back of the car had a surprising amount of dirt & grit inside them. I assume it gets splashed inside through the multiple small & large holes that are there to facilitate adding a receiver.



These boxed sections are going to rust right out. Make sure you spray your anti-corrosion gunk inside!

[ProDigit]

Probably from all the salt on the roads.
Here in Florida, any car, including the cheap Chinese vehicles, survive 100k miles / 10 years; after which the rubber (hoses, grommets, bushings, and belts will need replacing.
I've seen Elantras with 250k miles, as good as new here.
I'm sure the Mirage would outlast it's 300k miles engine here.

[foama]

Removing the hitch that came with my car, I discovered the boxed "frame rails" at the back of the car had a surprising amount of dirt & grit inside them. I assume it gets splashed inside through the multiple small & large holes that are there to facilitate adding a receiver.



These boxed sections are going to rust right out. Make sure you spray your anti-corrosion gunk inside!

The car below is from 2014, driven in the rust belt of Europe. See for yourself:








At age two the underside was thoroughly steam cleaned, all rust completely sanded away, undercoated, then painted twice with a synthetic resin paint. Should have done that on the brand new car, would have been less work. Used the same paint as for iron girders, bridges and ocean going ships. Your local painter knows what. When it was new, it received its first cavity wax treatment and six years later the second treatment.



De-rusting and painting was an entire day's work, but the results tell me it was well worth it!
This car is almost seven years old now, and from the European rust belt. The underside is as clean as ever, no rust and no proprietary sticky gooey stuff on the top of the non-existing rust.

The axle-bodies front and back, the wheel wells and exhaust were also de-rusted, and painted. They are totally rust-free today and have not been otherwise touched for years. That shows the comparatively small effort of treating a new car totally pays off!

[MetroMPG]

foama - your rust prevention looks great.

But I'm more concerned about rust developing inside those boxed sections.

When I removed the rear bumper & crash bar, I found a substantial amount of grit inside those frame rails. So salt & water has been getting inside too. That grit holds moisture.

Similar situation inside the front subframe.

[foama]

I was concerned too! Had a car that rusted away under my butt in no time, and didn't want to see that again.
Those boxed sections were thoroughly waxed with rattle can cavity spray when it was new and again several years later.
If I were to treat those areas on an older car, I would pressure-wash the the insides of the cavities first. A week or two later apply the cavity spray. On a brand new car I would spray paint the insides of the front axle body. I had to settle for cavity wax on mine after doing nothing during the first two years. Should have done it right from the start.

[MetroMPG]

Your Space Star is going to outlast every other one in Germany.

[foama]

Your Space Star is going to outlast every other one in Germany.

Better than quickly rusting away under my butt!

Seriously, it is not very much effort on a new car. If its already rusty, its going to be so much more work and effort.

[MetroMPG]

I've now seen this rust on 3 or 4 different 2014 Mirages. Pattern means design fault, not fluke.

Here's a very clear example from a recent for sale ad:



And here's my car:



You can just see 3 small bubbles forming, and small rust stains running down the paint beneath them.

At first I thought it must be a result of dirt/water/salt sitting on top of the in-turned flange of the wheel arch, but that's not it. The rust is coming through from the inside of a cavity in the wheel arch structure. Not sure how water is getting inside the structure, but obviously there's a lack of sealing somewhere.

Solution: find & seal the problem area, and/or make sure you get rust inhibitor inside the cavity on top of the wheel arch.

UPDATE:
Thread: CSI: rear wheel arch rust. Seal these fasteners!

[Fummins]

It seems like our fleet will be written off well before rust becomes a problem. just lost another one as I was walking out the door.

[MetroMPG]

Wow. Insurance must be crazy. Hope everyone's OK.

You can start shipping the rust-free leftovers east!