Rust appearing on tailgate-beware

Mazda refinished my 2008's tailgate with no questions asked. They wont, however, fix the underbody rust that's occuring. I hope they tighten up their corrosion resistance efforts because there is no excuse for it. The car just turned 30,000 miles, rarely goes out in winter, is washed regularly and lives in a climate controlled garage.

Hmmm... that doesn't look good. Perhaps undercoating asap would have prevented that? A little late now....

Caustic said:

Hmmm... that doesn't look good. Perhaps undercoating asap would have prevented that? A little late now....

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Yea, clearly the problem is with Mazda's rust protection. I have cars at work with 100k hard miles on them, no undercoating, and not nearly this much rust.

Have the same rusty liftgate issue and my service rep seemed unaware of any known problems or related TSBs, although the dealer body specialist knew exactly where the problem was once he was told it's on a CX9. He quoted me $475 to repair.

Mine also has rust on the underbody after 5 years, in fact one of the anchors on one of the exhaust shields completely rusted off. In comparison to almost no rust on the Volvo that the CX9 replaced.

radar_007 said:

Just bough my 2009 GT and I have the rust in the same location but opposite side. Was it covered under warranty?

I found a TSB 0901509 Mar 09. Does anyone have access to look at this TSB? I can't seem to be able to view it.

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http://www.mcx9.com/2007-Mazda-CX-9...ust-Around-Liftgate-Moulding/20110619557.html

Too bad I didn't look for this TSB before as my dealer said this wasn't a known/common issue even though I told my service advisor I have two friends who's CX9s have the same rust problem. Unfortunately my vehicle is now past the warranty period and dealer has denied coverage.

So I did exactly what I said I would. I took off this panel, ground out the rust that was forming around the Mazda badge and a little along the top edge of the trim. I then primed it, and used a Mazda touch-up paint stick. While the touchup doesn't look great - it is largely hidden by the trim piece.

I then used foam tape all the way around the sides and top edge of the trim piece - which, once attached, makes it so the only part that is actually touching the metal is the mounting bolts. If I did it again, I'd probably use a bit thinner of tape because the trim piece now sticks out a few mm more than I'd like. However, I do think it will prevent any future rubbing.

While I was working in there, I noticed (as have others) that the nuts welded to the backside of the liftgate for the licence plate were rusting and then the moisture was carrying the rust down inside the liftgate. Since the nuts were already rusting, I don't think there is much I can really do but I did hit them with rust convertor, then coated them with grease to try to prevent more moisture from getting to them. At the end of the day though, this is a design flaw which will most certainly produce rust inside the liftgate which will eventually bust through the bottom seam one day.

I also noticed that the rubber-coated holes where the mounting bolts for the trim piece go into had a little bit of rust colour around them. So I rubbed the rust off and coated those with grease as well.

Really, there are several rust issues with this liftgate. Everything I did this weekend will only delay the inevitable.

I'm another unhappy Mazda customer! Mazda put very little effort into rust protection if there is any. Last week I noticed couple rust spots on the lift gate between the small center panel and the large panel. The rust is certainly coming from the inside. The dealer refused to repair it because the two panels are rubbing everytime the gate is open or close. The problem is I can not see the rubbing from looking directly on the panels. They told me to go to their body shop and get it fix asap to prevent further damages.
Before I am taking my truck in the body shop I will contact Pro-Tech Seal first as I paid $1500 for the premium rust protection package. Has anyone made a claim with Pro-Tech Seal? Are they good company to deal with? I called but had to leave a voice mail as no one is available.
My 2004 Acura TL has less rust and less engine noise on cold start. Well, certainly my last Mazda!