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Undersealing


Gren
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Hello all,

I've just taken delivery of an almost-new (5 months old) Yaris Cross.  Enjoying it so far (I'll write up a review once I've had a few months with it).

Looking underneath, I was surprised how much of it was not undersealed - huge amounts of just painted metal.  The plastic underbody panels are ok to stop stones flying up I suppose, but surely salty water from gritted winter roads will still get into the space between the plastic panels and the lightly-painted metalwork.  Up here the council seems to pour salt on the roads like a siberian salt mine at the slightest hint of temperatures dipping.

I treated my previous car with lanoguard which seems to have protected it a bit, but I'm wondering whether the unprotected underbody is a problem for others, and whether you would recommend trying to remove the plastic panels to protect the metal behind them?

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As you say you live in an area that the council spreads excess salt on the roads this being the case then as it's a new car if you can offer as much protection to the underside as possible including regular cleaning it can't be a bad idea. 😀

 

 

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I believe that the best protection against corrosion underneath is regular washes. I am not a fan of any additional corrosion protection or sound proofing because often these have almost no positive effects but can actually accelerate rust formation. In addition to this any extra work may count as modification by the manufacturer and void any future warranty work. Basically adding anything to the car makes it a non original vehicle imo. 

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I had my first car underseal by the garage in 1964.  A bit like ceramic glazes offered by today's garages.  I don't see it as an insurance issue.

My second car too on 1966 was also underseal by the garage.  A badly designed wing panel rusted through.  Triumph replaced both wings as a goodwill gesture and I paid £17.

The garage that did the work 'spot undersealed' the wings.  I discovered the underneath was only red undercoat and a few specs of underseal. 

Clearly no warranty issue either.

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5 hours ago, Gren said:

Looking underneath, I was surprised how much of it was not undersealed - huge amounts of just painted metal.

But it probably has rust protection/inhibitor underneath - possibly galvanised if your lucky.

I've not seen much if any rust underneath over the decades. The killer places have usually been mud traps around the wheel arches, and sills which have rusted from the inside because they trapped moisture. Spraying the underside with waxy stuff won't fix those and manufacturers have largely eliminated those problems.

As @TonyHSD says, after-treatment might void any Toyota rust warranty, so tread carefully.

Personally I wouldn't worry about it - the underneath doesn't get as much abuse as you might think ... unless you ground it, in which case even extra protection will get scraped off. Salt is only a problem on exposed metal.

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Hi Ken, if you intend keeping the car for an extended period then something like lanoguard or waxoyl would certainly be a good idea.

If you're only going to hold onto it for three or four years, I wouldn't bother.

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Worst case of rust I had was on a Mercedes around 2003.  The drain plug in the boot was a bit blocked with dust and grit.  I poked it with a screw driver and it fell out.  The right boot panel consisted only of paint and underseal.  The corresponding left panel was in better condition.  In addition to the paint the spare wheel added some strength.

The repairs were quick and the cost modest.

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Thanks everyone.

I do tend to keep my cars for a long time, so worth protecting.  It's useful to know everyone's opinion as each different model has its own water and rust traps.

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Toyota vehicles (excluding Hilux) are covered by a 12 year unlimited mileage warranty on the metal body panels, protecting against rust perforation caused by a manufacturing fault. This warranty stays with the vehicle and transfers to any new owner.

Taken from Toyota's web site

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1 hour ago, Benzowner said:

Toyota vehicles (excluding Hilux) are covered by a 12 year unlimited mileage warranty on the metal body panels, protecting against rust perforation caused by a manufacturing fault. This warranty stays with the vehicle and transfers to any new owner.

Taken from Toyota's web site

You know when you open the bonnet, there's that metal bar that holds it up so you can do your thing. At the top where it originates from or at the base of it where you probably apply grease after some time, there is RUST. Out of curiosity, would Toyota consider that a manufacturer defect? I mean it's being used, yet the rust is there. Probably not in use for months at end prior to me purchasing the car, but then other hinges don't have this type of rust, hmm?

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Thing is Japanese cars are not protected underneath for British weather and they do rust 😕

Mazda seem to be one of the worst in this respect.

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3 hours ago, Hybrid21 said:

Thing is Japanese cars are not protected underneath for British weather and they do rust 😕

Mazda seem to be one of the worst in this respect.

My Mazda was really bad for that, rusty underneath on day one brand new.  The dealer sorted it, but only after I threatened to reject the car. 

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4 hours ago, Serban said:

You know when you open the bonnet, there's that metal bar that holds it up so you can do your thing. At the top where it originates from or at the base of it where you probably apply grease after some time, there is RUST. Out of curiosity, would Toyota consider that a manufacturer defect? I mean it's being used, yet the rust is there. Probably not in use for months at end prior to me purchasing the car, but then other hinges don't have this type of rust, hmm?

They'd probably say that it's not a body panel, and it's not 'perforation'. 

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14 hours ago, Gren said:

My Mazda was really bad for that, rusty underneath on day one brand new.  The dealer sorted it, but only after I threatened to reject the car. 

I had a brand new MX5 2013, and was shocked at the amount of surface rust underneath at the first MOT.

I really had intended to keep that car for a long time as it was a second car, not used much and fun to drive.

But the rust underneath swayed me to get rid. I've got a 1987 Golf GTi with less surface rust underneath 😕

 

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I agree with the op about the poor protection underneath, and particularly suspension and subrfames, and there's all sorts of dirt traps that the covers don't really protect. I've experimented with various products over many years and the likes of Waxoyl are the worst (apart from old fashioned underseal) and just allow corrosion to carry on worse underneath. I've found lanolin based thin oils best, but must inspect, clean and keep repeating regularly, at least yearly to stay on top of it 

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  • 1 month later...

I am thinking about using Lanoguard for the underside of my 2006 Corollo Verso. Has anyone else used it and is it as good as the makers say?

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I think the underneath should be as clean as you can get it, apply lanoguard then repeat yearly. As it's a thin fluid it shouldn't allow moisture to creep underneath. Do inside box sections etc, suspension and subrfames are particularly poorly protected. Ultimately, the best you can do is slow it down. A modern car can look good on the outside because of all the plastic covers but it can be a different story underneath. It isn't something you can do once and forget, you need to clean, inspect and re-do often 

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My MX5 ND (2018) was undersealed and all cavities treated from day 1 with a 10 year guarantee and ceramic coated with a 9 year guarantee - I plan to keep it so worth the expense. My 1993 MX5 has never been on a salted road and shows little or no rust, just surface discolour; when back from it's respray it will be undersealed/cavity treated.  My Yaris will be getting a similar, but lighter, treatment as well.

On the MX sites, there are horror stories of rust, Scottish MX5's seem to suffer and there are sayings such as "never buy a Scottish MX5" for, probably, a very good reason - the required liberal application of salt on the roads.

Fairly local to me is this company, not used them yet but that's where I expect to take the cars.

https://www.cskautomotive.co.uk/the-rust-prevention-centre/

CSK Automotive
Buntingford,
SG9 9JS

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I would agree,  and I would never buy a second hand car from the north of Scotland due to the amount of salt put on the roads.

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33 minutes ago, Hybrid21 said:

I would agree,  and I would never buy a second hand car from the north of Scotland due to the amount of salt put on the roads.

Hi Iain,is the second hand car market in Scotland slower then elsewhere as I assume most motorists are aware of this salt problem. Has this also affected the prices.?:smile:

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I bought a Mercedes from Birmingham.   The first thing my garage man said was this has never been near the coast.   His garage was five miles from the coast and he serviced cars from the coastal strip.

We also used vehicles on the sandy beach.  We lost a 2nd hand Landie in a year.  The 2nd hand Toyota pickups fared far better lasting more than 3 years.  All the vehicles were washed daily and one Toyota even spent a couple of days on the beach.  The cab was filled with sand to the windows.   A quick hose down and it was back in service.  Jeremy eat your heart out.

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Since my days of running older cars I've dreamt of having a fully sealed waxoil or similar undercoating to prolong the life of the car.  However, I've seen one two many videos on YouTube of cars (usually in America, those big trucks they love to drive) having been taken off the chassis, and the undercoating is everywhere under the car, but missing from the top of some key suspension components etc.  Obviously, rust will still take a foot hold unless it's 'completely' covered. 

Leads me to believe even if you get it done, there'll still (most likely) be spots missed despite even a professional's best efforts. 

Another thing I'd say is, if it's all sprayed and sealed (and done as well as possible) it might still look like a bit of a mess, and other parts might get covered in the process. I'd worry that that could even lead to MOT fails from inspectors who don't want to get involved with looking closer to check for corrosion / damage in the later years and just fail it.  That's how it is in NI anyway as we can only use the government MOT centres and not independents, maybe not an issue if you've a relationship with a local garage (or have them carry out the sealing). 

Although it might look like bare metal, the whole body of modern cars are all galvanised and pretty safe anyway, certainly for even a long typical life of a car like a Toyota. If you know you're going to keep the car, well beyond any reasonable service life, could be worth doing. But for all the expense and hassle and risks, give it a good bit of thought. 

Personally when I wash mine most weeks, I be sure to get the Snow Foam lance well under and give it a good soaking with some pre-wash stuff to break down any nasty saltiness (who knows if it works). Helps me sleep a bit better at night lol 

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6 hours ago, Bper said:

Hi Iain,is the second hand car market in Scotland slower then elsewhere as I assume most motorists are aware of this salt problem. Has this also affected the prices.?:smile:

Hi Bob, the second hand car market up here is still very strong and doesn't seem to be affected by the salt problem.

When I refer to up North I mean north of Stirling. I live in the central belt on the west coast, and although the roads are salted, we do get a lot of rain which probably washes the salt off underneath on a regular basis.

My daughter resides in Aberdeenshire where the roads are heavily salted throughout the winter, and I certainly would never buy a second hand car from that area, but it never seems to bother the people who live there 👍

 

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8 minutes ago, Hybrid21 said:

Hi Bob, the second hand car market up here is still very strong and doesn't seem to be affected by the salt problem.

When I refer to up North I mean north of Stirling. I live in the central belt on the west coast, and although the roads are salted, we do get a lot of rain which probably washes the salt off underneath on a regular basis.

My daughter resides in Aberdeenshire where the roads are heavily salted throughout the winter, and I certainly would never buy a second hand car from that area, but it never seems to bother the people who live there 👍

 

Hi Iain, beautiful place Scotland but you really do get some bad weather that's for sure mate.:smile:

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