Rust appearing on tailgate-beware

[sbmrinaldi]

I was switching out my wifes plates on her CX-9. One of the damn screws is busted off and will not come out. As I was working on this I realized small bubbling of the paint behind where the plate mounts. I am 100% sure this is the beginnings of rust. It appears the water is being trapped behind the plate cover and holding moisture against the paint causing rust. I will get the Mazda dealer today, but needless to say I am very upset. Her CX-9 is 2 years old and sits in the garage all the time. It has less than 15,000 miles. I am not a fan of repainting.

[CX9 SportOwner]

Maintenance, not defect

And its not the water, it's the grit and salts that do that. If you rinse the car off well regularly, including underneath, the engine, tailpipes, and behind the license plate, you won't have this problem. The water will evaporate, the dirt does not.

[sbmrinaldi]

Not so sure that is accurate. I keep her car clean. It is the cleanest 2 year old car with 15k.

[tb88]

My wife had rust appearing on the corner of the rear trim piece above the license plate holder. The dealer had it for two days and had to order parts, disassemble and I'm not sure if any paint had to be done. We live in a snowy/salty area but she keeps it rinsed quite often. I wonder if there is a seal or gasket on that piece that somehow lets in moisture.

[sbmrinaldi]

Are you talking about the rear license plate or the front? On the rear there was nothing to hold the plate, just two screw holes in the rear deck. The front has a bracket but the whole front end is just plastic. We will see what Mazda has to say, but I am not confident it will be a positive response.

My wife had rust appearing on the corner of the rear trim piece above the license plate holder. The dealer had it for two days and had to order parts, disassemble and I'm not sure if any paint had to be done. We live in a snowy/salty area but she keeps it rinsed quite often. I wonder if there is a seal or gasket on that piece that somehow lets in moisture.

[CX9 SportOwner]

It is possible there was a paint defect letting water and grime in. Otherwise, rinsing the nooks and crannys well with water will prevent 99.9% of rust problems. That said, it would be nice of car makers to provide 4 threaded stand-offs instead of the typical 2 or 4 threaded holes on the flat sheet metal. Then dirt wouldn't collect so easily.

Until then, I wash well, and a couple of times a year take the plate off and wash behind the ears. again, clear water doesn't cause the rusting. It's the dirt eating the paint, and retaining the water longer than normal evaporation would take.

[tb88]

Are you talking about the rear license plate or the front? On the rear there was nothing to hold the plate, just two screw holes in the rear deck.

It is the trim piece above the rear license plate where the light bulb shines on the plate.

[CX9 SportOwner]

Same principal. There is a tight gap between the plastic cover and the sheet metal. Any dirt collecting there will erode the paint and retain water. a regular blast with a hose will fix that. Unless it was a paint defect to begin with, but even then thorough washing will help.

[brightwhite]

The tailgate on our CX-9 GT is doing the same thing. Every single seam on the tailgate is covered in rust bubbles (there's about 12 of these spots on it). Our car is regularly rinsed throughout the winter. Dealer is going to repaint for free. I have a feeling that this is an issue that many people are going to start seeing. Our car has 24,000kms on it and is a 15 months old.

[CX9 SportOwner]

Did the dealer offer right away, or have to be talked into repainting?

[brightwhite]

Offered right away, I didn't have to demand it, although I was prepared to.

[CX9 SportOwner]

Sounds like it may be a know paint problem on a few CX9's then. Possibly the primer, or improper washing of the release agent. If it was a maintenance issue, they wouldn't be so quick to eat the cost. A repaint now is cheaper for Mazda than replacing your rusted through liftgate later.

I'd ask the dealer if they've heard of this problem, and exactly what caused it, if you haven't already. If they haven't issued any notices, they may not know which VIN's are affected, and are just handling it as the problem occurs.
Better than the way Honda handles known problems. They just keep quiet and make the owners pay for it, which is why we didn't buy a Pilot (that was before the CX9 came out)

[brightwhite]

dealer claimed they had seen a few, so it may be a known issue with them. I'm glad they've offered to repaint.

[sbmrinaldi]

Dealer is getting my wifes car in this week to repaint the tail gate. I am not a fan of repainting, but it is getting fixed and is on the rear of the vehicle as well.

[CX9 SportOwner]

Have they said what caused it?

[sbmrinaldi]

Have they said what caused it?

They didn't say. They just called and said Mazda will fix it and supply me with a rental car. It is getting done this week and I will pick it up tomorrow.

[CX9 SportOwner]

Definitely a known issue. I'll put a dollar in for release agent.

[dave245]

Mine has the bubbles as well, after only 1 winter. I have not checked it yet this year...

[Neuritis]

My new 08 CX-9 has this problem too. The dealer got the bodywork estimate and once they have approval from Mazda Canada, they will repair.

Update: The repainting was completed in 3 days. Looks good now although I don't know if the underlying cause of the rust was fixed. They had to remove the CX-9 logo so I am now incognito (still have the Mazda logo though).