Trex08

How odd that gm undercoated some and not others. I wonder what determined which ones they would do. I guess seeing that none of us are worrying about voiding a warranty, I might end up doing mine. Is it just the wheel wells that were factory undercoated?

Oldblue

In mine yes, but I live in winter salt belt! I have my rust proofing done when I bought it, it's worn off mostly now just over 8 years later

Blue_SS

I used to work in GM Paint Engineering back in the day. The issue is the weep holes or drain holes in the doors and liftgate especially. There are holes placed there by design to drain the internal moisture, and stuff like undercoating or Ziebart (ironically, the surname of one of my high school friends who was much better playing keyboards than anything automotive...)can clog them. Ziebart can be especially bad. They TRY to seal everything up.

I would certainly not add it without careful consideration of whether blocked drain holes will lead to increased rust, rather than the intended improvement.

If you have it already, it's no panic situation, especially if , like Fireman George, you never see salt.

Bottom line is, these dealer add-ons CAN void the GM Corrosion warranty, and this is why.

Trex08

In my case, I am thinking of just hitting the fenderwell, may or may not use a little fluid film on the bottom inside edge of the of the doors, because my previous panel started to bubble and rust there. From what I can tell that is the only susceptible area that starts to rust out first.

Again, I don't think any of us have any warranty left...do we?

Blue SS, how you liking the blue flash? I switched from white to blue flash, really liking it, but the white hides everything, so I'm picking out every little flaw on the blue.

a_bartle

I have used "Rust Check" (only in Canada) and as of late "Krown" a local place in MI. Their process is more of a thick "oil" that they spray inside door seams and the under body. It seeps/wicks into all the cracks and seams. It doesn't block any of the weep holes, but is is kind of messy for a while after application. I have it done every other year or so, I really believe it's a good product. I think the last time I had my HHR sprayed it was $125.

skyline26

I agree with a_bartle.

I im Ontario Canada, and our roads get salted like crazy and takes a toll on our cars for sure! I take it to "Krown" which soaks the hell out of the car in their oil which does an amazing job! Much better compared to "Rust Check" (they are a joke compared to Krown)

Id suggest getting it sprayed by Krown every year or every other year. Its about $100-130 depending on location. But well worth it! It does drip and cause a mess for a couple days, but I dont mind that since it does such a good job getting into all the crevices of the vehicle