Jimny rust proofing

Jimnys don't rust as much as MX-5s do! The weak spot in a Jimny seems to be under the boot floor although it's said later ones are galvanised (like VW Group cars) and therefore should never rust at all unless damaged and repaired. Does anhyone know for sure about the galvanisation?

Rust is on its way back with a vengeance on modern cars - except the galvanised ones - because the emphasis on crash safety and light weight means very complex box sections and lighter gauge steel. Auto Express did an eye-opening feature on this last year. Bad rotters include Mazdas and BMWs.

Incidentally, it's an urban legend about JDM MX-5s not being rustproofed like UK ones. They are exactly the same. The MX-5 Mk1 and Mk2 have a bad moisture trap just ahead of the rear wheel arch, where the sealant around the lip of the arch fails and water starts to get into an undrained cavity. The base of the A-pillar also rusts, as does the base of the front wing.

The Jimny, being a body-on-frame car, can pass an MoT with colossal amounts of rust as long as it's not causing jagged edges. A unibody car, like the other 99% on the road, can fail if bad rust of found near any number of structural points. A body-on-frame chassis is never going to rust through because it's so thick, having to take all the loads on its own.

rogerzilla wrote: Jimnys don't rust as much as MX-5s do! The weak spot in a Jimny seems to be under the boot floor although it's said later ones are galvanised (like VW Group cars) and therefore should never rust at all unless damaged and repaired. Does anhyone know for sure about the galvanisation?

Rust is on its way back with a vengeance on modern cars - except the galvanised ones - because the emphasis on crash safety and light weight means very complex box sections and lighter gauge steel. Auto Express did an eye-opening feature on this last year. Bad rotters include Mazdas and BMWs.

Incidentally, it's an urban legend about JDM MX-5s not being rustproofed like UK ones. They are exactly the same. The MX-5 Mk1 and Mk2 have a bad moisture trap just ahead of the rear wheel arch, where the sealant around the lip of the arch fails and water starts to get into an undrained cavity. The base of the A-pillar also rusts, as does the base of the front wing.

The Jimny, being a body-on-frame car, can pass an MoT with colossal amounts of rust as long as it's not causing jagged edges. A unibody car, like the other 99% on the road, can fail if bad rust of found near any number of structural points. A body-on-frame chassis is never going to rust through because it's so thick, having to take all the loads on its own.

Suzuki told me that it is not galvanised.


the problem with modern cars is not necessarily the thickness of the steel. but the use of water based paints, causing rust to take hold right from the start.

Paul.

If there is any galvanising, it will only apply to the exterior panels- eg. wings and doors- the ones that everyone can see if they go rusty. I haven't ever sen a Jimny with rusty wings so this may well be correct. Peugeot have been galvanising panels since the late 80s. I'm sure many other manufacturers have done too.

As for chassis not rusting because it is so thick- that's not the case with some cars such as Landrovers, where the chassis can rust through in just a few years.

This forum portrays the Jimny as a rust bucket but I think that's quite unfair, given the age of many of them and the fact the rust is non structural and non cosmetic (e.g. can't be seen from the outside).

Its to do with the moisture traps, and the quality of the steel.

My old Jeep had an open sided C section chassis, made of some sort of alloy steel, and not a trace of rust, but you could put your hand through the few of the body panels that hadn't already been swept up with a dustpan & brush.

All the Landrovers that I have owned have had rotten chassis, and rotten alloy body panels too (Aluminium doesn't rust- it disappears into a white dust, faster if it is joined to anything made of steel)

facade wrote:
All the Landrovers that I have owned have had rotten chassis, and rotten alloy body panels too (Aluminium doesn't rust- it disappears into a white dust, faster if it is joined to anything made of steel)

So true, why they mixed steel and aluminum is beyond me.

originally, it was because postwar steel was rationed for a good few years after, whereas aluminium was not.

and even after steel rations were lifted, they stuck with it for two reasons. 1 it kept the weight down, and 2, their tools weren't strong enough to press the same panel in steel.

3 it was advertised that the aluminium would cause less corrosion!