5th Gen rust prone spots?

A few weeks ago I bought a new 2021 4runner. In theory, I want to keep this truck a good while, and like most who live in the heartland, hate rust. I think today will be the last day I'm able get under the truck and protect it. I use Amsoil HD metal protectant, and when I traded in my Tundra, after 3 full winters, it looked rust free, so....

I searched this forum and am trying to get peoples thoughts on the troubled spots to focus on. I don't do the whole thing, because Toyota does a pretty good job on coverage already. I just want to hit the spots that through wear and tear ,(road grime ,friction, splash spots, hiding spots etc) will create the bad stuff.

I'd like to think this will help others, especially the guys/gals who get under the truck and see the spots, and can help current and future owners.

Either way, I'll be under the truck this afternoon anyway to get this done.
Thanks!

 

One thing I’ve noticed with my wife’s 2018 was around the welds seems to start showing rust the first. So when I bought my 2020, I made sure the frame was clean and I took POR15 and painted over each weld. If you look at the welds, you can see spots that look like they could be a future problem. It’s all vehicles though. I did the same on my 2020 Wrangler. POR15 is some good stuff. Just wear gloves and long sleeves.

 

I've negative experience with POR15 because it didn't convert rust but rather just covered it in strong I must say paint coat which later chipped of in big flakes. I use rust converter now followed with frame paint with much better results.

 

One of these days, maybe Toyota will finally get an handle on the rust problem...even newer vehicles, you gotta keep a eye on them..as the rust is like cancer, it spreads.....

 

Yea rust is brutal. Right now since I literally have no rust I figure now is the time to do it. I dropped the spare, sprayed up there, and the corners of the frame area I thought would be bad, from previous experience. I'm sure I did more than needed but thats ok. I used 2 cans. It's kind of like a clear with a tiny hint of brown yellow when it sets up. I'm a fan.

 

Ugh, I guess I'll get that in the morning before work. Much appreciated!

 

That is one of those tedious under car, overlooked, jobs that can bite you in the butt later on. It's a good excuse to get under the rig and have a look around.

 

I use 3m body panel wax for cars but i had 4R undercoated at 2k miles before winter with Krown undercoating from canada, which is now in the u.s., at least in PA. Krown had great reviews and is similar to body panel wax and an older rustproofing called rustfre from years ago
All 3 do well. I drove a 72 ford to 215k miles no rust when PA rust killed cars. Im taking my 4R and 2 other suvs i had done back for an annual refresh and check. About $150 each trip. i have 3 cans of krown that i touch up when underneath for oil changes and work but no tools for inside body panels.

 

Hi all, looking for undercoating advice. My rig has 6K miles on it and fortunately has been driven in only one or maybe two situations where it would have picked up road salt etc. I'd like to get an undercoating done. Prob Fluid Film or similar. Is there something I should do to prep the vehicle beforehand? Does it matter if the undercoating is applied to surfaces that aren't pristine? Or maybe a good service place would be sure to prep it first? Thanks much.

 

Use wool wax or fluid film only. If it already has surface rust, take a wire brush and then hit it with rustoleum rust reformer and then fluid film or wool wax