New owner, need advice regarding rust and maintenance

[axios]

Hey everyone!

I'm a new 4Runner owner. We just bought a 2006 with only 30k miles on it! My hope is to keep it until it dies, so to that end I was hoping for some advice because I think the frame is going to rust through long before the engine poops out on me.

The original owner never undercoated it or did any rust prevention, so after 12 years in the salt belt there's a decent amount of rust on the frame/undercarriage. The mechanic told me there were no holes yet, but that there might be soon. I went and did an undercoating a couple of days ago ahead of all the snow and salt on the roads, and they're suggesting I come back next year for some rust removal with a scrub/brush and another undercoat. There's also the more expensive option of using a rust converter which would remove up to 80% of the rust (they quoted me $600).

What's the best thing for me to do in terms of maintenance? Is there some way to actually fully remove the rust or is it probably too late now? And is it possible to get an assessment of how many years of life the truck has left on it? None of the mechanics I took it to wanted to give me any kind of estimate... I'm hesitant doing some of the more expensive upgrades like bumpers and roof racks if it's only going to last another 5 years, whereas if I can keep it going another 10+, it might make more financial sense.

Thanks for any help!

 

[ZebRuaj]

We'll, we can't determine if its surface rust or the early stages of frame rot from your description. You'll have to determine that, then see what your next steps are and if it's worth modding.

I hope you didn't get the black tar undercoat stuff. Just saw Eric O from SouthMainAuto rip a frame apart that had that for undercoat.

 

[axios]

I got this stuff: NH Oil Undercoating, it's some kind of mineral oil, definitely not a tar, but not sure exactly what's in it. They said it penetrates through the rust down to the metal, but who knows if that's just marketing. The reviews seemed good though.

I guess to properly examine the frame I'd need to get a mechanic to lift it up and look in all the nooks and crannies?

 

[Inv4drZm]

Posting pics will help us a bit more, but at only 30k miles, if it's salvageable, make sure it's fixed 100% correct. Don't cheap out, you're starting in a hole so to speak.

 

[axios]

Posting pics will help us a bit more, but at only 30k miles, if it's salvageable, make sure it's fixed 100% correct. Don't cheap out, you're starting in a hole so to speak.

I just went out and took some photos, hopefully this helps... I went with a clear undercoat so that it wouldn't obscure the rust. Apologies about the poor angles, mud, etc.

Here are the photos.

Thanks for the help!

 

[4RunnerIdiot]

The problem with rust is... it allows for more rust to form even if it's under a coating. I would say that the proper order here is to remove as much rust as you possibly can with things like an angle grinder with a wire brush attachment, then do rust converter on anything that's left, then use a fluid film-like undercoating once a year or as often as needed.

 

[Jdevtac]

I just went out and took some photos, hopefully this helps... I went with a clear undercoat so that it wouldn't obscure the rust. Apologies about the poor angles, mud, etc.

Here are the photos.

Thanks for the help!

Have you taken a hammer and screwdriver to the frame or did the mechanic that inspected it? Sometimes what looks like surface crud and feels relatively solid, ends up being a hole. I just bought a 4th gen with this issue. Check the rear trailing arm mounts on either side of the frame, both the exterior metal section of the frame where it’s welded, as well as on the underside of the frame up inside the trailing arm mount. Seems passenger side is usually the one to have an issue first.

Also if you have the trans cooler you should check the lines running along the front most frame crossmember, where the front skid also mounts to. Mine. Will need replacing but aren’t leaking yet.

My plan with my rust situation is get my frame fixed, on top of already having Eastwood internal frame sprayed the entire frame. I wire wheeled any surface rust, used a phosphate converter on such, then painted it. Final icing on the cake is a coat such as fluid film or one of my preferred, Corrosion X, and then let it be. That’s the best anyone can do really. I don’t trust POR15 as it likes to delaminate from anything it doesn’t like to stick to, which usually means existing factory frame coating.

Edit: the other thing I forgot is I bought some cheapo endoscope cam to inspect the inside of the frame where I couldn’t see. There was a healthy amount of surface rust on the inside along the frame weld seam. And lastly I inspected all the quarter size holes on the under side of the frame looking for delamination. Stuck my finger up through them to feel for flakey paint/metal.

 

[axios]

Have you taken a hammer and screwdriver to the frame or did the mechanic that inspected it? Sometimes what looks like surface crud and feels relatively solid, ends up being a hole. I just bought a 4th gen with this issue. Check the rear trailing arm mounts on either side of the frame, both the exterior metal section of the frame where it’s welded, as well as on the underside of the frame up inside the trailing arm mount. Seems passenger side is usually the one to have an issue first.

Also if you have the trans cooler you should check the lines running along the front most frame crossmember, where the front skid also mounts to. Mine. Will need replacing but aren’t leaking yet.

My plan with my rust situation is get my frame fixed, on top of already having Eastwood internal frame sprayed the entire frame. I wire wheeled any surface rust, used a phosphate converter on such, then painted it. Final icing on the cake is a coat such as fluid film or one of my preferred, Corrosion X, and then let it be. That’s the best anyone can do really. I don’t trust POR15 as it likes to delaminate from anything it doesn’t like to stick to, which usually means existing factory frame coating.

Edit: the other thing I forgot is I bought some cheapo endoscope cam to inspect the inside of the frame where I couldn’t see. There was a healthy amount of surface rust on the inside along the frame weld seam. And lastly I inspected all the quarter size holes on the under side of the frame looking for delamination. Stuck my finger up through them to feel for flakey paint/metal.

Excellent information in here, thank you. I haven't taken a hammer and screwdriver to it yet, no. I don't think the mechanic did, either. He just had a look with a flashlight, he wasn't very thorough... I guess I need to do this myself. Did you end up raising your truck or were you able to do all of this just crawling under it?

And good idea about the endoscope cam!

 

[Jdevtac]

Excellent information in here, thank you. I haven't taken a hammer and screwdriver to it yet, no. I don't think the mechanic did, either. He just had a look with a flashlight, he wasn't very thorough... I guess I need to do this myself. Did you end up raising your truck or were you able to do all of this just crawling under it?

And good idea about the endoscope cam!

I did not end up putting it on a lift because I don’t have access to one unfortunately. As such there are still a couple areas that were too tight to get to. It was annoying actually because I’m used to working under a 2nd gen Tacoma with a 2” lift so I rarely need to jack it up unless it’s suspension work.

Now if I could just invent a time machine and go back and slap the orginal owner into regular rust prevention I would lol.

 

[cooper30]

That looks really good to me for anything that old around this area (I see you are in NH).

If it was mine....barring any actual soft spots....I'd Fluid Film the hell out of it and call it good. Use the real stuff, not the aerosol cans. Repeat every fall.

 

[T4R2014]

No painting. Just fluid film and you'll be fine.

 

[Jarheadoo7]

Fluid Film will stop the rust and if you keep applying it seasonally, keep it away.. its a messy job, especially if you do it on jack stands and from spray cans, but its good stuff.. Get the hose adapter so you can push the hose into the frame and spray inside the frame ..

I just checked your photos, that undercarriage has been painted, I would set aside a Sunday to get on your back and poke at everything under there..

 

[grave]

Have you taken a hammer and screwdriver to the frame or did the mechanic that inspected it? Sometimes what looks like surface crud and feels relatively solid, ends up being a hole.

this!

The problem with rust is... it allows for more rust to form even if it's under a coating. I would say that the proper order here is to remove as much rust as you possibly can with things like an angle grinder with a wire brush attachment, then do rust converter on anything that's left, then use a fluid film-like undercoating once a year or as often as needed.

and then this!

knowing truly how much is down there and how bad it is is really up to you. don't just let some mechanic tell you whatever they want to to get some money out of you, and **** the mechanics that didn't want to give you an estimate. put your big kid pants on, get your truck on some jack stands and your ass on a creeper and get under your truck with an angle grinder and some safety glasses/goggles. and then seal it however you see fit.

 

[4RunnerIdiot]

this!

and then this!

knowing truly how much is down there and how bad it is is really up to you. don't just let some mechanic tell you whatever they want to to get some money out of you, and **** the mechanics that didn't want to give you an estimate. put your big kid pants on, get your truck on some jack stands and your ass on a creeper and get under your truck with an angle grinder and some safety glasses/goggles. and then seal it however you see fit.

Full-face safety shield. When you're under there, angle-grinding directly above your face less than a foot away, screw goggles/glasses. I get great looks from the neighbors when I walk out into the driveway wearing this

 

[grave]

Full-face safety shield. When you're under there, angle-grinding directly above your face less than a foot away, screw goggles/glasses. I get great looks from the neighbors when I walk out into the driveway wearing this

probably smart. those ****ing wire wheels will shoot little flecks of metal brush at your face like it's nobody's business. i had to wire wheel an entire stakebed work truck frame and i would find those shits in my jeans at the end of the day. like the movie twister when the stake goes flying through the barn wall.

 

[Jdevtac]

probably smart. those ****ing wire wheels will shoot little flecks of metal brush at your face like it's nobody's business. i had to wire wheel an entire stakebed work truck frame and i would find those shits in my jeans at the end of the day. like the movie twister when the stake goes flying through the barn wall.

I find getting rust chips sling into my ear holes to be the most annoying part. I wore some ear pro the second time I climbed under my 4runner lol.

 

[kgbagent]

I don’t trust POR15 as it likes to delaminate from anything it doesn’t like to stick to, which usually means existing factory frame coating.

Amen. My experience with POR15 was just this. And, yes, I prepped it according to POR15's instructions. I had much much better results with a wire wheel, Rust Reformer spray, followed by Rustoleum high performance enamel painted on. This is more of a "permanent" solution. Fluid Film is very temporary.

 

[Jdevtac]

Amen. My experience with POR15 was just this. And, yes, I prepped it according to POR15's instructions. I had much much better results with a wire wheel, Rust Reformer spray, followed by Rustoleum high performance enamel painted on. This is more of a "permanent" solution. Fluid Film is very temporary.

It has its place but I don’t think a rusty frame is one of those places. Seems to do well for expendable/attachment items like bumpers and sliders. I actually used it in restoring some OEM 16 hole steelies and it’s held up pretty well. Still wouldn’t use it on my frame lol.

I’ve done pretty much the same as you described. Wire wheeled. Hit it with a rust converter and then followed with Duplicolor engine enamel with ceramic. I like the duplicolor as it’s held up amazingly well on the steel wheels I mentioned. Best you can do over top all that is something like fluid film or whatever to then really exclude moisture.