Ultimate Undercoating Argument Thread

We all know our own opinion is the right one, and everyone else is wrong!
Just like we all know how Royal Purple is the only good engine oil, Red Line makes the best diff fluid, K02s are the best wet-traction tire, etc.

This thread is your chance to share why your grandma's bar chain oil + diesel mix is the ONLY good undercoating solution! So, which undercoating do you use, and why are you right? You're only allowed to share correct opinions here. And if you don't live in a salt state, we don't wanna hear about your unrusty life.

*i hope the sarcasm is clear^ but I do think it can be helpful for folks to see various options, hear personal experiences, and get opinions*

 

Who told you about my nana’s undercoating recipe?

 

I use Surface Shield because I'm gullible and I got conned into it by a Youtuber.

 

Papaw's mouth doesn't stop running after a few drinks at the American Legion!

 

I use Rust Check dripless clear gel because my local Rust Check does a better job with the spraying than my local FF, Krown, and Corrosion Free shops. You should be asking in your local/regional forums (doesn't have to be Toyota-specific) for referrals.

 

FF. Takes 20 mins, 2 cans, once a year. The Texas heat helps.

 

Roofing screws are better than FF, change my mind.

 

You understand the spirit of the thread. Except there is nothing to argue with here, you are simply speaking the truth.

 

Woolwax told FF to change their recipe and they didn't listen, that's why Woolwax isnthe best.

 

So this truck was treated with FF when new?

 

I have used both fluid film and surface shield. They both are pretty similar. I like surface shield better because it sprays out of the can with a thicker stream so less of it ends up blowing around and hitting the ground. It’s also a dollar cheaper per can.

 

Whatever this guy uses and bugger welds:

https://www.youtube.com/watch?v=oJ4qYHUQpKQ&t=385s

 

Dealership undercoated mine when new. Still waiting for the frame to fall apart any day now...

 

Mr. Turd, this thread is for arguments only. Your post is far too nuanced.

 

Dealership probably injected rust actually, but don't worry, self-tappers will fix it right up!

 

Used FF on my Tacoma, but on my 4Runner I’ve been using Amsoil HD Metal Protector- last several years, dry to the touch and IMO easier to apply, FF nozzle “spits” too much

 

It doesn't matter what I used, its the best, and anyone who uses anything different is stupid and their truck will be garbage in 3 months.

 

THAT’S THE SPIRIT. You tell em syeve!! In fact, it doesn’t matter if you use the same product as me, you used it wrong because I bet you didn’t coat the inside of your gas tank!

 

I’m sure it costs twice as much as something comparable just because it says amsoil on the can.

 

Actual it’s cheaper… 15.75 oz 11.75 oz

 

nobody can beat Surface Shield for $6 at Harbor freight during 30% off sales! Except grandmas diesel + oil mix of course.

 

I should argue with you in the spirit of the thread, but I am curious about a few things: does this stuff creep? What’s removal like? And it doesn’t truly dry hard right? Cuz that usually is bad meaning it’s trapping moisture underneath. This product kinda looks like CRC corrosion inhibitor which I’ve heard is awesome and you can get a 6-pack of aerosol for $49 on Amazon.

 

No, displaces moisture, very similar to the CRC stuff.

 

https://youtu.be/oXlhmbvdKBo?si=htH5BFWxwiGWIwNW

 

Not just any self-tapper. Professionals use roofing screws - they have a rubber washer to keep moisture out.

The only place self-tappers have in your truck is mounting remote reservoirs for dune jumping, where corrosion doesn't exist. That's why Icon supplies self-tappers for their most expensive shocks: https://images.iconfigurators.app/pdf/Icon_Dynamics/I57810P_REVC.pdf

 

Never did an undercoat on my 4R and I have minor rust. Wonder what would be good to use that won't trap the rust and stop it from rusting more?

 

You've come to the correct thread for your question. I use the only good product and I found the only way to do it right! Click here for my thread about it... but seriously, there are some good suggestions on this thread: Fluid Film, CRC Corrosion Inhibitor, Amsoil MP HD, Woolwax, roofing screws, etc. They're all better than nothing and the important thing is to avoid product that traps moisture. This Youtube video is why I chose Surface Shield.

 

All the thin-film sprays discussed here (FF, Rust Check, Corrosion Free, Krown, Cosmoline, CRC Marine...) satisfy your scenario; they are quite tolerant of poorly-prepped surfaces. For DIY rattlecan use Cosmoline or CRC Marine as they are more durable.

 

This works great.



Wrong forum? (seemed to fit for some humor in the thread!)

 

Only works on the rear end.