Front frame rust starting... 106K mile 2014

I've got an '11 in eastern Canada (Salt galore) that wasn't undercoated until I got it. I've got a load of small spots on the front subframe with the paint all gone and surface rust starting. The rear jack points have some surface rust on them, and the sills have a couple spots, largest being by the drivers door. The passengers sill has a little hole by the back tire. Oddly, the floors are almost perfect. Most of them seem to have the sills rot out, but the rest holds up pretty well. If you undercoat them they fair much, much, better.

fj5gtx said:

So I figured I would revive this thread, I sprayed fluid film over the areas and its not gotten any worse. I think to fix it, all the plastic underbody covers in the front need to be removed... then wire brush and some chassis saver or kbs coating to provide a more permanent fix.

However since I started this thread, I have seen multiple cruzes with rocker panel rust through. Seems to be the first outer body area to show internal rust issues. I plan to spray some fluid film inside those rockers when it gets warm.

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Yeah in the year since I made that comment the ends of my rocker panels got significantly worse and I wound up needing the ends patched, I do strongly support filling them with fluid film to avoid this.

GM also uses fabric bags for sound deadening in the wheel liners (I believe VW does as well), and they tend to get filled with **** over the years, and begin to rot the fender or quarter above them. I tore mine out when the timing belt was done, but unless you live somewhere with a lot of salt & brine it probably isn't a concern.

A family members cruze has been undercoated since new with a couple missed years, and it is spotless underneath and the rockers being filled with krown has helped immensely with the rockers, with the ends just starting to show the tiniest amount of rust on the metal bit behind the fender liner after a decade of use every winter.

fj5gtx said:

I checked out a junk yard cruze with rotted rockers. I didn't see any factory holes that would aid getting fluid film (or equivalent) sprayed in there. I guess I'll be drilling a few access holes unless someone tells me I'm overlooking something.

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Mine has some holes on the bottom of the rockers with these rubber plugs in them that I think are factory, although they don't let you get much in, drilling would be the move. I've been told by some guys at Ok-Tire that do undercoating that there are specific spots to drill into the rockers from under the car, but have no clue as to what they would look like.