Sierra Frame Wax Touch Up

gmtruck10 · October 30, 2020

Hello,

I'm new to this forum and just recently purchased a 15 Sierra 1500. I understand GM's frame wax coating and I have a few visible rust spots where it has peeled off and needs to be touched up. I purchased a can of the Nox-Rust X-121B and plan to wire brush these spots first then apply rust reformer and finally the nox rust. Would I be ok doing this? I do plan to one day have the wax removed entirely from the frame and do POR-15. Also does anyone recommend getting rear frame plugs to cover the holes? Would that help in preventing rust forming in the tubes? Thanks!

acinquegrana · October 30, 2020

I use that stuff. Works good. I use that and a combo of fluid film (or recently woolwax which i like better). I dont recommend por 15. Its just a headache. Needs to be done perfectly or it just gets worse. Woolwax offers black too so thats a perfect combo. With the woolwax you just remove heavy flakes and cover the light rust. It neutralizes it. The wax coating on the GM frames is junk. If you dont cover it in fluid film or woolwax from new.. you are fighting and uphill battle. See pics of my 2016 thats driven in New England since new. 45k miles. I have been undercoating since i got it. ZERO rust. And for the frame plugs... Don't do that. Water can still get in through the little holes at the bottom of the cross members and needs to drain out the sides. You want airflow through there. Just load it with woolwax/fluid film and you're good.

You can take the rocker panel plugs out too and do them and shoot it up into the doors.

What i do is:

Noxrust. Let it dry for a day. Then, cover the entire undercarriage with fluid film / woolwax. The only down side is a mess when you work on it but I don't mind.

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acinquegrana · October 30, 2020

One other warning. If you use fluid film or woolwax, it will soften up the GM coating. That's a good thing in my opinion since it penetrates through and no way for water/salt to get behind the coating. Stick with woolwax it firms up a little better than fluid film does. Much thicker.

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gmtruck10 · October 30, 2020

45 minutes ago, acinquegrana said:

One other warning. If you use fluid film or woolwax, it will soften up the GM coating. That's a good thing in my opinion since it penetrates through and no way for water/salt to get behind the coating. Stick with woolwax it firms up a little better than fluid film does. Much thicker.

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Awesome, thanks for the advice. I think I will try the rust-oleum rust reformer/nox rust combo for the areas I see for now. It will be something I need to pay attention to every year.