Rust on a Japanese used car: the body matters more than the parts

When you find rust on a car you're thinking of buying from Japan, the first question isn't how much there is. It's where it is. Rust on a part that's bolted on can be dealt with by replacing the part. Rust on the body itself, the panels that are welded together and can't be unbolted, is what decides whether a car is worth buying. Listing photos rarely show either.

The body: panels that are welded on, not bolted on

I call the body shell the box. When I judge a car, the box is what tells me most, especially the panels that are welded on and can't be swapped by undoing bolts:

• The strut towers: the part of the body the front suspension is mounted to
• The rear wings (fenders)
• The underside (see photos of my own car's underside, taken from the ground)
• The roof

There are two reasons. First, once a panel like this has been repaired, it tends to rust more easily afterwards. Second, a car with a solid box is often a car in good condition overall, and that counts for even more on an older car.

For where these places tend to go on particular models, see our model pages, for example the strut towers on the Nissan Skyline GT-R R33 or the front frame rails on the Silvia S13.

Rust on a part: my own car

My car, a Toyota Prius α, comes from Hokuriku, a snowy region of Japan, and it has a lot of rust.

The rust at the top of the front suspension is on the strut itself, the suspension part, not on the strut tower it's mounted to. The lower part of the strut is rusty too. Replacing the strut assembly would take care of it, and for the part you can see from the engine bay, replacing just the upper mount would clear the rust. You can see the photo on our page about what dealer photos miss.

So on this car the rust I've shown is on a part, not the box. But a car with this much rust may also have rust spreading under the paint, so it isn't something to ignore.

Are cars from Japan rust-free?

You'll often read that cars from Japan don't rust, and on some cars that may be true. The reason usually given is that Japan doesn't salt its roads. That leaves out how much of Japan gets snow. Japan's land ministry designates "heavy snowfall areas", and they cover about 51% of the country's land, where about 15% of its people live. Where a particular car spent its life is something to ask the dealer: where it was registered and used, and whether that was a snowy area.

As for the idea that Japanese cars don't rust, my own view is different. Japan is hot and humid, which is good weather for rust. There's sea air along the coasts, and salt damage in the snowy regions. I think cars in Japan get more rust than cars overseas, which is one more reason to look at the box.

I also think the rust protection underneath Japanese cars is thin, though it depends on the model. Some have a real weakness: on the R33 and R34 GT-R, for example, the strut tower is poorly protected on the wheel arch side. See our R33 GT-R page for how that happens.

That's my opinion from looking at cars here, not a measurement. Every car is different, so the only way to know about a particular car is to look at it.

How to tell body rust from part rust

• Ask what the rusty thing is held on with. If it comes off by undoing bolts, it's a part, and the question is what replacing it would cost. If it's welded to the rest of the car, it's the body.
• Look at the four places above first: the strut towers, the rear wings, the underside and the roof.
• Don't relax because it's only a part. A car with a lot of rust on its parts may also have rust spreading under the paint.

If you're buying from photos alone, my advice is simple: whatever else you get, make sure the rusty spots are photographed.

If a listing says "rust free", treat that as the seller's words, not as something you've seen. Ask for close photos of the four places above instead: the strut towers, the rear wings, the underside and the roof.

Stone chips on the bonnet

In my view, a lot of stone chips on the bonnet (hood) usually means a car that has done plenty of motorway (expressway) driving. Chips that have been touched up are a sign the previous owner looked after it. Left alone, chips on a steel bonnet will rust. And they hardly ever show in a listing photo.

If the underside has been coated

If the underside has been given a rustproofing coat, in my experience you can't tell what the rust is like any more. Neither a camera nor anyone standing next to the car can see through the coating. So on a coated car, we can photograph what can be seen of the coating from ground level, but not what's under it, and we mark that as Not verified in the report.

What photos can't tell you about rust

• How far it goes. A photo shows the surface. It can't show how much metal is left under it, or whether rust is spreading under paint that still looks fine.
• Whether a panel has been repaired before. A repair can be hard to see, and a repaired panel can start to rust again later. We photograph what we can see. We don't certify whether a car has or hasn't been repaired.
• Most of the underside. Without the car on a lift, much of it can't be seen properly. We look from ground level and don't lift the car, so anything we can't see is marked Not verified in the report. On a car that's been lowered a long way, we may not be able to see much underneath at all.
• Which rust matters to you. A spot that would put one buyer off is easy for another to live with. That's your decision, not ours. We don't tell you whether to buy.

Worried about rust on a particular car? Tell us which parts of the box you want photographed, and we'll look there first, as far as can be seen from ground level.

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If the car is a long way from us

We mainly cover the Tokai region: Aichi, Gifu and Mie. For a car elsewhere in Japan, ask us and we'll quote the travel before you pay. If a visit isn't practical, a Remote Check is where we phone the dealer in Japanese and ask for photos of the spots you name. See On-Site Vehicle Viewing for what we look at in person.

Written by Yoshiaki Sagara, a paintless dent repair and detailing technician in Japan. He looks at cars for overseas buyers through Ninja Desk Japan. About us

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