POR15 on a new car frame

[denwood]

I can only assume Toyota doesn’t apply this to their frames/sub frames, only hidden cavities right?

If they do then it obviously doesn’t work by the looks of my ES350 and Tacoma…lol

They don't, but they should! Noxudol 300 is the black/heavier bodied partner to 700. I use those two exclusively now on our vehicles as the 300 is the only product that survives our salt/sand winters without washing off. I normally use about 200-300 ml of the 300 each fall for touch ups on heavily exposed areas. 700 doesn't need to be redone typically inside the panels.

 

[Cujet]

What kind of semi permanent rust preventatives are there?

This is about the best of the affordable products, for external surfaces:
It is an Aerospace grade product, tough and easy to use. Works really well on driveshafts, suspension parts, struts, and sheet metal. Use the thinner Corrosion X inside seams and doors first. As the thin stuff will wick into welded seams.

 

[Bluestream]

Noxudol 700 for inside panels which is just as important, it is sold in rattle cans with a wand and Noxudol 750 or 720 for the under side and frame.
Fluid film doesnt even come close to the protection level of Noxudol. Toyota spec'd Noxudol for its new replacement frames and is OE on other manufacturers.

Its not rocket science, all you need to do is provide a barrier between the steel and the oxygen in the air/water. Ive used this product for 35 years and it cost $16 per 4L However, only keep my vehicles 20-30ears