Rust on frame on my 06

[Steve-Maine]

I have quite a bit of surface rust on the frame and cross members of my 06 GMC 2500HD. I was looking at spraying it with Fluid Film. I read someplace that rainwater will wash it off. I live in Maine where they use a lot of liquid salt on the roads. Is there a better undercoat that can be applied over rust I think what ever I use will have to be spayed on. Thanks for any help.

[ClutchDisc]

I did it on mine, shop said it would be good and that it would adhere to the surface rust. In my opinion it was $200 wasted.....year later and not much of the stuff is left on. Save your money....It's a losing battle anyway.

[hockeypro1411]

Look into a product called POR15

[kstruckcountry]

Lots of people seem to like Krown.

[C/K Man]

The best thing to do is to reapply the factory wax rustproofing. The factory material is Nox-Rust 121B, and it is available in aerosol cans from Daubert Chemical (www.daubert.com). It goes over the existing coating and metal with surface rust just fine, and will not wash off. POR-15 can only be used if ALL the existing wax coating is removed, and most of the other oil based 'rust-proof' coating won't last one season. Also, many of them are bad for flexible brake lines and wiring harnesses.

[Grumpy Tooch]

try spray on rust inhibitor then use a thick undercoating like rhino lining or something. When I had my bed done I had them spray the whole undercarriage too and wheel wells. They didint do a very good job but it is protecting pretty well, and I dont live in Maine...

[sdeeter19555]

Two things...

 

There are several versions of Fluid Film...the thin one will wash off (been there, done that), but the thicker one seems to hold up well.

 

You can also oil undercoat, which is very popular in the rust belts. Basically the underside of the truck gets hosed down with oil (either new motor oil or used hydraulic/transmission fluid).

 

I've done both...I oil-undercoated all my other vehicles, and had the Silverado sprayed with Fluid Film a month ago. I actually touched the Silverado up with oil because nobody ever does it "the way you want it done". On my last two trucks, I could loosen any bolt underneath with regular tools, no rust whatsoever; even with nearly 300k miles on the clock. I prefer oil, it creeps into the seams and folds where things can be sprayed.