So I’ve been talking to general mechanics (non Toyota specific) in my area who are steering me away from the 4Runner. They are saying they have major corrosion issues up here. 9 out of 10 are shot. Look great on the topside but lots of issues with ANYTHING steel underneath from fuel lines to steel cooling system components, suspension, fuel tanks etc.

Coupled with what I’m reading about rotten frames, rockers, a arms and differentials, it makes me worry.

I know this is an enthusiast site so there will be some or possibly much bias.

Can I get the skinny on what to expect IF I can find a well oiled 4th gen?

Are there inherit issues ignored or overlooked by enthusiasts because their capability overrules the maintenance factor?

I’m looking for something that will go 400+K (Kms) with regular maintenance, yearly oiling and little or light winter use for the rest of its lifespan

Please give me the real world skinny on 4th gens in the heavy rust belts.

My car has spent it's entire life in the rust belt. I purchased my 2007 sr5 April 2020 with 157k miles on it. I've always wanted a 4runner and know and had the same worries about what you're talking about. It's all random. I know a buddy who has a 3rd gen and it is SHOT. Mine just has the typical weld point rust issues and some small surface spots that i've already sanded and cleaned up. I wouldn't let it shy you away from wanting one. Just take your time, find the RIGHT one and take the precautionary measures to maintain in.

So I did have an 03 that had a rust hole and wouldn’t pass inspection after ~15 years. I then got an 08, which so far is in good shape.

I think the the earlier Toyota frames have a lot of issues with rust in the salt, it seems that in general the later 4th gens seem to be doing better 06+ and the 5th gens though not perfect have better frame protection from rust

I still anticipate that rust will be what ultimately does my vehicle in - before massive engine failure

But I think getting to 400k is a reasonable goal for the 4runner

If you like the 4runners, I wouldn’t let it scare you away. Do a good inspection and as long as you’re taking care of it by keeping an eye on rust and spraying off the salt best you can I think you’ll be okay.

4th gen rust/known maint. issues for buying used??

4th gen rust?

Question for Northerners about rust

Should I avoid buying in the Northeast?

Good threads there. Thanks.

I’m going to TRY to be patient and very selective.

Look for vehicles that were sprayed often

If you can get one from California or Texas (stay away from the beaches areas) and bring it over might be best.

When it comes to repairs, things tend to go out in 2’s or 3’s and end up having to do mult jobs at once.

Happened to my wifes Acura tl too.

...and Stick to 06-09 4runners

Good luck

My wife's 07 came from Colorado. I just replaced the suspension and everything was rust welded. I had to use breaker bars and saws awls which added many hours to the job.

All those you tube videos on non rusted parts are misleading.

Tbh its kinda random. Mines been in Illinois 17 years and I would bed it could go another 5 easy. You have to expect there to be some rust, paint flaking. What to look for is if it crumbles or gives easy. Wouldn't be a bad idea to sand what you see, spray some reformer and other paint over it just to slow it down.

I had a 3rd Gen (2000) that I kept for 18 years in Illinois & Ohio - finally sold it for salvage after welding the frame three different times. Just purchased a 4th Gen (2005) that is very clean for it's age - it had been Ziebarted when new and maintained well. I applied Woolwax to the underside and intend to keep that up annually. Did not get to the 2017 Tundra before winter set in but intend to do the same to that next fall.

My 06 was an Ontario rig its whole life and its very solid aside from the typical surface scabs and what not. First thing I did when I went to see it was roll around underneath it for 20 minutes checking the frame, then put it on a lift to check it even further, clean bill of health. It was one owner garage kept cream puff though, your mileage may vary. 150k miles. I had it sprayed by corrosion free to keep it this way too!

FYI that rubberized undercoating is terrible stuff

Rubberized Undercoating Will Destroy Your Car! - YouTube

Just make to buy a 10 foot breaker bar...

Yes, some truth to your mechanic's statement. Especially buying used, its hard to find a clean one. They are out there. Also, with care, like washes and fluid film the steel underneath will last. Take your time, find a well-cared for example. Then keep it rust free with some extra car washes and a corrosion preventative of your choice.

took me looking at 3 of them before i found one in RI with acceptable corrosion.

its since been garaged and i sanded and painted a few area, stay on it. trick is finding one thats 'clean' around here

i remember one of them i looked at seemed so promising. took a look under the vehicle and walked away. literally. the salesman called his mechanic to bring the truck in the garage as i walked away. he knew he made a mistake buying it; i didnt

I don't think it's much different than any of the big 3 pickup trucks of the same age except the bodies last longer. You have to watch the frames on Chevy and Ford closely too plus the rockers, wheel wells and cab corners. Check the T4R out thoroughly even one you know is rusty so that you can get a feel for the typical locations they rust. Mine needed patching on the driver's side under the front seat area and by where the back tank strap attaches. Also watch those straps and they rot. Many have issues with the front cross-member where the tow points are, for some reason mine isn't too bad. I did have to replace 95% of my brake hard lines. My truck is an 03 so getting old.