4Runner Rust

I’ve read plenty of post about Fluid Film and Wool Wax being needed for the under carriage. Is this just a Toyota issue? Does it also pertain to Lexus? Is it a geographical issue related to salting roads or is it a Toyota thing? Trying to understand why it is needed.

 

^Yes the 4Runner and GX460 have basically the same frame, built in the same plant, and go through the same anti-corrosion coating and painting processes. Most vehicles are susceptible to rust in regions with salted roads. 4Runners happen to have reliable powertrains so they're worth protecting for longer-term use.

I read parts of the US like upstate New York switched from road salt to even more corrosive (but supposedly environmentally friendlier) deicers, and it's typical for vehicles to fail inspection and head to the salvage yard after 10 years, if rustproofing isn't done. Think about 2014 4Runners going to the crusher en masse.

 

I wonder how long an average frame lasts with salt in the Midwest and treated each fall. Ten years with no treatment? I realize it’s all subjective in time and salt

You’re right though 2014 going crusher is insane. I’d be ticked for all this cash and good engine

 

We got lots of salt on roads in Ontario, I had 2010 SR5 and didn't do any rust protection at all. After 11 years it was quite rusty underneath, but not close to any mechanical failures due to rust. I think it would lasted another 4 years easily. So I think that 14 years without any rust treatment is realistic. But I treated my new 4Runner with Fluid Film since rust doesn't look pretty and who knows maybe I'll keep my 4Runner more than 15 year or keep it as an off-road toy.

 

That’s pretty bad wow 11 years. Here’s to hoping fluid film works for the 15 plus for you.

 

True, it’s bad for a well running 4runner. But suppose it goes to the 15 years mark without structural issues…is it that really bad compared to anything else?

I sold off an 06 Sienna that i bought new. I did nothing to prevent corrosion. By the time I sold it with around 220k miles late in 2021, it had enough rust that it was starting to become a maintenance issue, but not yet a structural issue. In that sense, it was still serviceable, but I no longer wanted to do what was needed to be done to keep it at 100 percent for daily commuter duty (200 miles per week), and long trip duty. That said, it probably remains serviceable today for the current owner. He picked it up for a steal (low $4k range), and was willing to spend the money on some of the more expensive scheduled maintanace I disclosed was due (transmission oil change, Spark plugs, timing belt, water pump).

So to me, my Sienna lasted me around 15 years, but there’s little reason it couldn’t still be running around somewhere. If you can do that with a 4runner, I would say it’s getting your money’s worth for just about any vehicle.

If you take anticorrosion efforts for the 4runner, it’s mostly a benefit for people intending to keep it a loooong time. I still think that 4runner owners in the salt belt should take measures, even they plan on short term trade, just because it’s nice to the next owners

 

Most cars rust out wherever roads are salted in the winter, just part of the game. Body on frame Toyota trucks have a bit of a worse reputation with this and even resulted in that the frame recall years back......but honestly, I take a peak underneath even 5 year old American body on frame trucks around here and they already look like the Titanic. Frames are hollow and can retain that salt water inside them longer than they should, rotting the frame and making the truck essentially worthless. Most people aren't consistent with washing the undercarriage of salt in the winter too.

If you have a truck that is currently in good shape rust wise and you plan to keep it a long time, definitely do an oil based undercoat every year. If done correctly, the condition it was in when undercoated will be well maintained as long as you keep up with the annual undercoating. It's not an expensive service to pay for too.

If doing yourself, fluid film is good stuff. If paying someone to do it, I highly recommend Krown, as they also shoot coating inside body panels to prevent any body rust. I usually do all my own maintenance, including fluid film on my 3rd gen, and was happy to pay for the Krown treatment on my new 5th gen (as were my neighbors who didn't have to endure smelling fluid film for days!).

If you change/trade in cars often like most people, I wouldn't sweat it. Most dealers in the rust belt taking in trades wouldn't notice or even think its abnormal to see some rust underneath, probably wouldn't value your 4Runner more being rust free than one with typical surface rust tbh. Just rinse the undercarriage off more frequently in the winter and you'll be fine.

 

They salt roads where I live. Both myself and my in-laws hold on to cars for a while. However, my approach is different. Each fall I treat cars I drive in the winter with Krown. This is messy and requires extra clean up. It is also messy to work on. When I move on from a car, typically between 8 - 12 year old, they are rust free. I also get above-market price when selling them privately.

My in-laws do not rustproof their cars, but they do wash the salt off regularly. We hold on to cars about the same time. They sell them when surface rust becomes noticeable. They sell these as-is, on the cheap, and to the first person that shows up with cash. Other than rustproofing, they take good care of the car. I have purchased cars from them for a winter beater and they tend to fall apart in 3-5 years after that due to rust becoming a structural concern or specific repair, usually suspension, becomes too expensive to justify doing it.

Here are my observations and conclusions:

1. With rare exceptions of design flaws (e.g., something traps salt and water), yearly Krown from new is a very effective way to prevent rust. Once rust set in, Krown only slows it down.
2. Rust is not limited to body panels and frame, but also impacts brake lines, electrical connectors that run outside the car. Rust also makes any kind suspension work spiral out of control (e.g., drilling bolts, torch, etc.)
3. Premium you get for selling your car is equal about the total cost of rustproofing. It is not significant for someone able to afford a new car.
4. If you buy new or slightly used and sell the car before 8-10 year mark, and don't work on it yourself, you are rustproofing it for the next owner. However, you ARE shortening car's overall life by neglecting this.

While I personally had to take cars (still running and driving!) that was purchased by my in-laws to a junk yard, I have seen cars I sold still on the road at 20 year mark. I think it is wasteful and bad for the environment to not rustproof your car, but it is reasonable approach from purely economical point of view.