GEN 4 Jimny undersealing

Bob1050 wrote: if the Jimny is assembled from zinc coated steel.....

A pretty big if. I doubt it very much

Anything that thickens up the paint where the stones are going to hit it is a good idea, anything water displacing and anti-corrosive inside the box sections is better, the Gen 3 rotted from inside the box sections and double skins.

I've tried engine oil, ACF50, NATO fluid (smells just like JL69 to me) waxoil and dinitrol over the years. and dinitrol actually seems to reduce corrosion long term, I've cut rusty metal off sills that have been waxoiled inside and the waxoil hasn't soaked into the rust, it just lifts off leaving dry scale underneath. ACF 50 and the NATO fluid are ok if you keep spraying it on. (Same as engine oil really)

Bob1050 wrote: Think carefully about what you are trying to achieve - if the Jimny is assembled from zinc coated steel, then adding 'underseal' will have a very limited impact on the speed at which the underlying steel rusts. It will offer some barrier to stone chips and for some folk might be more attractive cosmetically. Any anti-corrosion properties are not reaching the steel itself - they will sit over the factory applied finishes. Little harm in applying any of the off-the shelf 'waxy' type finishes but the jury might be out for a long time before the benefits are realised. I've sprayed a few vehicles myself - lack of trust in commercial applicators. If you are comfortable using a £1 household plant sprayer and have a can of your favoured material - then you can do it yourself and know it has been thoroughly done. The Jimny is a small vehicle so I don't see it being a big job - could be a bit messy though!

This is why I recommended Bilt Hamber DYNAX UC because it's clear! It wont detract from your new gen.4's gleaming underside and you cant make an 'ugly job of it' just build the coats up on the areas susceptible to the most rust i.e Axles, suspension, running gear, arches

On other equipment sites I have looked at on other issues often the manufacturer steps in to the discussion to put their perspective. It would be good to hear from Suzuki on this matter given the poor reputation for rust their vehicles have and the somewhat random pattern of factory undersealing applied to the GEN 4 (at least mine). To clear up issues such as zinc coated steel, why the warranty is voided if underseal applied and why they have confidence in the way their rust prevention treatment is currently done. It looks to me like a rust bucket in waiting.

Hi. I spoke to Suzuki and they confirmed that it would not invalidate any warranty. I have that in writing and will be keeping the email should I need to make a claim in the future.

Thanks, that's not what they told the dealer from whom my Gen 4 came, the opposite in fact. I will contact them directly. Do you have a contact email for this kind of thing at Suzuki?

Really struggling to understand on what grounds the application of a 'wax' type coating on the underside of a Suzuki Jimny would invalidate the warranty. Think that is a 'pub talk' rumour - never seen any real evidence of it happening. If you did an invasive deconstruction of the vehicle in order to apply a coating, or created such a mess that no tech would want to work on it - there might be reasonable grounds to dismiss some warranty related claims. I say this as someone who has never had a warranty claim rejected and suffered major transmission problems after I treated the underside of a vehicle and then returned it to a main dealer.