Stopping frame rot.....

My tacoma is in very good shape, but when i stick my finger inside the boxed portion of the frame i can feel a bit of scaling going on, on the bottom of the frame rail. I just had an idea and wanted some opionions. What would happen if i where to seal off the drain holes and pour a bunch of gear oil in the frame would that be a viable way to curb the rust forming or is it a dumb idea. Like literally fill the frame with oil then seal it off with the oil still inside... and maybe add a couple breather tubes on each rail for condensation to escape

 

Putting oil in is a good idea, but first you must remove as much loose rust as possible, to make sure the oil gets to the frame and not just on the rust layer that is on top of it. There is no easy access to the inside of the frame, but there is a few things you can try:

Compressed air through the square holes on the frame rail

some tube wire brush you can put on a drill

pressure wash it through the square holes on the frame rails. Though if you do so, you must make sure the water doesn't stay trapped inside your frame. Make sure your drain holes are not clogged and park the truck in direct sunlight for a few days to make it evaporate

Then when you are done with cleaning the inside of the frame, put the oil in. I don't think you need to leave the oil in there. Fill it then park your truck on a slope to make it go everywhere and coat the inside of the frame, then drain it through the drain holes. If you leave it in there, if there is dirt or anything getting into your frame, you will have a dirty soup of mud, dirt and any crap that managed to get in. Might even attract moisture in. Or to make it simpler, you can apply some fluid film, as it is excellent for this kind of usage.

Also, NO brake fluid/oil, as it attracts and absorbs moisture, so it will make your frame rot

 

https://www.tacomaworld.com/threads/rust-prevention-treatment-consolidation-thread.355928/

 

Fluid Film. Gear oil seems like it would be incredibly messy, not to mention environmentally irresponsible. Fluid Film is a lanolin based material that stays "active" in that it will continue to creep into cracks and seal them up.

Fluid Film is not a permanent product, though. It needs reapplication a couple times a year.

Or, get the Eastwood Inner Frame coating. It is designed for exactly what you're describing. 17 bucks a can. I have four cans that I'll be spraying into my 99 here in the next week or so, so I'll be able to comment more on how many cans you'd need.