Yaris Underbody

[Keith276]

I just bought a 2009 1.3 three door Yaris with only 45000 miles on it. It was a private sale with only 1 former keeper, FSH and the lady i bought it off was really genuine which made a nice change to be honest, as looking for a good yaris has made me feel like i live in another country and almost everything is CAT something or other.

The car looked mint inside and out. The spare wheel and tools have never been removed from the car and other than two really tiny dings on the passenger side and some corrosion on a wiper arm the car looked like it was new. I had a quick look under the car and noticed a little rust, but i still thought it was a great find so i bought it.

A few days after buying i bought the stuff needed to treat the rust i noticed under the car and went to work on it. After getting right under the car i found that the amount of rust under it is almost unbelievable for a 2009 Toyota. I spent three full days working under the drivers side, removing as much rust as i could with wire brush tools on a drill, kurust treating the bare metal, putting three coats of silver hammerite paint on the whole drivers side underbody and then waxoyl underseal.

I park the car facing the other way on the drive to start work under the passenger side and wow...you would think this was built in the early 90's!!! The lip that runs along the bottom of the sill (where the jack fits over) is looking like it will be rotted through close to the rear wheel arch when i start to remove the paint from it.

We have an old 53 plate yaris with 132000 miles on it that we have abused for well over six years and there is almost no rust under the body and the lips running along the bottom of the sills have zero rust on them. Did Toyota purposely do something so their cars wouldn't last as long or what?

I checked the MOT history of the car before looking at it and its never failed and MOT and the only advisories its ever had were on the last MOT and are for the offside rear wheel bearing being slightly noisy (on the long drive home i would say it was more than slightly noisy) and the nearside rear wheel bearing has slight play. The lady who i bought it off had her three MOT's done with the dealers who she bought it from, so im wondering if that has put them off saying the underside has lots of rust.

I find myslef in a tough position having a car that looks, smells and drives like new and with only 45000 miles on it, but knowing the underside is full of rust.

[furtula]

When the rust starts, i don't really trust that undercoating as it just makes things worse, it does not hold that long, and when it does let go, tiny cracks hold water and accelerate the decaying process.

Personally i would get some grease and mix with oil, apply, and "dust" it some roads.  I'm sure you remember some old oily cars, when you wipe that 5yr old residue, the paint is shiny and new underneath, even after all the winters etc.

The car is now 10 years old, and if it's in such condition, i would expect some bodywork issues in 2 years.

[Stevie J]

Strange that is, as I have a 2006 Mk 2 Yaris with 30K genuine miles on clock (it was my mother's before I owned it, and she rarely used it), and there is only light surface rust on the underside, and on the usual suspension parts, but no evidence of severe corrosion, and this car is 13 years old now.

On my previous Yaris Mk1, a 1999 T plate CDX, it failed the MOT  with severe corrosion all down the rear sills and the inner wheel arches on the rear, with massive holes caused by corrosion, and that car had 65K miles on it at the time, being 14 years old, I also had to replace a rusted out fuel filler neck pipe which also had massive holes in it at the top caused by severe corrosion. so Mk1 Yaris models can suffer from bad corrosion. The photos below are of my 1.0 CDX when it failed its MOT and the areas that had failed - all on the rear sills and inner wheel arches.

[Keith276]

Thanks for the replies and photos. It seems to me that the 5 door versions are more prone to rust in that sill to wheel arch area than the 3 doors.

I've never even cleaned the underside of our 53 plate yaris in the 6.5 years we have owned it and its got zero rust along the sills, the lip of the sill or inside the wheel arches. Just a few tiny bits of very light rust far under the car.

 

This black waxoyl spray is supposed to never crack and always stay sort of tacky, but i know what your saying about underseal cracking.

[Stevie J]

It may have been that the early Jap built Yaris Mk1 models (99 - 01) were not rustproofed as well as the later French built models from 2002 onwards. Any Mk1 with a VIN number starting JTD will be a jap built model, and VNK will be French built.

It seems that even on the Mk2, the area in the inner rear wheel arch just in front of the wheel forms a dirt and moisture trap, so I imagine this will be an early failure point for corrosion if any of the undersealing fails there. Its one area I keep my eye on with my current 06 model, but as yet there is no evidence of holes or weak spots forming there like they did on my 99 Yaris. On looking further on my 06 Yaris,  on the inner sill areas and along the bottoms of the sills where the jacking points are, there is evidence of light rust forming. It also appears to have a fair amount of corrosion on the rear suspension crossmember, springs, and other areas around the suspension mounting points on the back of the car, so I may have to get under it during the summer and paint some underseal on, before that slight corrosion becomes MOT failure type corrosion. I guess at 13 years old, I must expect some corrosion, even though there is only 30,000 miles on my current car.

Compared to a Nissan Micra Mk2 and Citreon Saxo I used to own, they really were rot boxes underneath and severe corrosion affected the sills and chassis underneath them, the Yaris is pretty good where corrosion is concerned, but I dont think any car is immune from underbody corrosion after the age of 10 years old.

[Keith276]

I didn't know the French built any of them. One thing i have always respected Peugeot for is the corrosion resistance.

I am happy with the drivers side half that i have finished working on and i'm confident there won't be any problems from there for many years, as i got the rust down to clean bright metal and it now has a hell of a lot more paint on it than when they make them.

Come weekend and if its not raining, i will start work on the passenger side and if the worst bit, which is the last 7 inches or so of the lip at the bottom of the sill ends up being ok, then i should be able to do a proper job of sorting it all out and hopefully make it last longer than any other standard factory Yaris underbody.

[FROSTYBALLS]

4 minutes ago, Keith276 said:

I didn't know the French built any of them. One thing i have always respected Peugeot for is the corrosion resistance.

The Yaris has nothing to do with Peugeot - they are built at Toyota's French plant near Valenciennes.

[sproutdreamer]

I feel for you-our 04 T Spirit was extremely rusty underside and previous MOT advisories made me wonder if I should just scrap it at only 46K.. I used a power finger sander for 3 days and shifted all the rust (I found that much better than a power wire brush). I then started with Hammerite but quickly got bored with that and just went straight to bitumin underseal mostly brush but also spray cans for the difficult bits. I fortunately found no rot just lots of rust but all good now and the test only had advisories for the rust in areas I did not get around to.

Car is French build but was kept in Scotland where they use lots of salt in Winter?

[Keith276]

2 hours ago, sproutdreamer said:

I feel for you-our 04 T Spirit was extremely rusty underside and previous MOT advisories made me wonder if I should just scrap it at only 46K.. I used a power finger sander for 3 days and shifted all the rust (I found that much better than a power wire brush). I then started with Hammerite but quickly got bored with that and just went straight to bitumin underseal mostly brush but also spray cans for the difficult bits. I fortunately found no rot just lots of rust but all good now and the test only had advisories for the rust in areas I did not get around to.

Car is French build but was kept in Scotland where they use lots of salt in Winter?

Its a dirty horrible job isn't it. My face was jet black by the end of each day and even though i was wearing protection glasses, my eyes were full of bits and were giving me a lot of pain for a good few days afterwards. I was doing the noisy work in the day and ended up putting coats of paint on through the night up until 4am one night. I have never been so cold in my life as i was that night.

I'm only going to have Sunday to work on the other side this week, so it looks like the job is going to drag on for another couple of weekends. I just want it over and done with.The fuel filler neck will need changing before long by the looks of it, as that is yet another steel part that is just protected by a very thin coat of paint that would have probably started rusting within months of the car being on the road.

Toyota could and should do a much better job at protecting the enderside of their cars. I looked under my Dads 56 reg Focus last weekend and its MINT under there and thats a car thats known to be a rust bucket.

[Stevie J]

The fuel filler pipe from the tank to the filler door flap, is very prone to damage on the Mk1 as it has no shielding from the spray from the rear wheel. On the Mk2 this was improved by a plastic shield being fitted to the rear of the wheel so you can no longer diectly see the fuel filler pipe by looking into the rear wheel arch.

On my Mk1, the first hint there was an issue was the smell of petrol fumes at times when standing round the rear of the car, especially when it was parked in a garage. There are 2 pipes side by side, the main filler pipe and a smaller diameter breather pipe that runs behind it, and the top of the breather pipe where it enters the main pipe at the very top, behind the fuel filler flap compartment, was where it was completely rusted through, with most of the pipe actually gone completely, totally eaten away with corrosion.

We could only obtain a new filler neck pipe with its integrated breather pipe from Toyota's spares dept at that time, and from what I remember it was about £75, and that was back in 2010, so I imagine they will be a good deal more expensive nowadays. I do remember when we fitted the new pipe, we painted it with underseal to try to preserve it, as its unprotected location, exposed to spray and road debris being thrown all over it from the rear wheel, means its not going to stay corrosion free for very long.

The one other area I remember now that was an issue was the rubber connector between the main body of the car and the tailgate, which carries the cabling into the tailgate from the roof of the car - this was forever popping out of its housing in the rear of the car's roof , and it lets water into the subsequent hole if it pops out, so we ended up using silicone sealant round it to hold it in position. The same type of rubber connector is also on the Mk2, but so far this has not been an issue on my current car. The photo shows the tailgate open, and the rubber connector can be seen at the top right of the picture - where it joins to the car's roof is where we found it kept pulling out, and had to be sealed in to prevent water ingress.

Another area we had issues with was corrosion of the factory alloy wheels, the type as shown on the pic below - this lead to a poor seal between tyre and rim, and we had issues with tyres losing pressure on a regular basis, meaning we ended up replacing the wheels with aftermarket alloys. My current model does not have alloys, just steel wheels with plastic trims, which are also corroding, but as yet dont lose pressure from the tyres.

[franny49]

I have had my 2007 Yaris since 2007, never a problem. 126,000 miles on it now, well cared for. Mechanic just told me that it will probably NOT pass the October Dept Motor Vehicles inspection due to underbody rust. Not sure how to procede. Thought I should take it to another mechanic for second opinion as a start. I love that car and I would like to keep it but knowing how things are here in the states I doubt anyone will take on job such as the rust removal and protectant. Are there any other options to correcting the issue. I know my Yaris is based on a Unibody and just wondered if that is something that might be replaced. I am not mechanical and a 70 year old woman, so whatever I do has to be done by mechanics. I would love to hear suggestions. Thank you. 

[sproutdreamer]

Some of the underbody parts are bolt on and replaceable. The cross beam at the back, the wishbone suspension arms however the mountings for the suspension arms are very prone to rust as are the sills which is a welding job. At 126k miles and with much rust it is probably not an economic repair unless you can find a friendly inexpensive body guy who can weld it up.

I would ask on this forum for a recommendation for a body welder in your area, it is more a case of finding somebody who can and will do this and may not be too costly. Good luck with it.

[wildtapholer]

You never said which part of the country you bought the car from, my wife's first Yaris I bought her was from a garage at Scarbrough and suffered the same fate, red rust underneath due to the salt on the coastal roads, I just changed the engine oil and put it through a spray gun and sprayed it under the car, when all the dirt from the road collects on it, it gives a nice water proof coat once all the dirts built up. 

[Sheepy]

Are toyotas not covered under their 10 year anti perforation warranty. If its rusting due to poor manufacturing then they should be covered. Obviously not the older cars. 

[TonyHSD]

The biggest enemy to all cars and the cause of rusting parts is the salt and grit that been spread on the roads during winters and driving style (use of the car)  the second will define whether a particular car will have or have not rust. Same cars of same age and mileage can have a significant difference in rusted parts.

1. Usually cars that had been used mainly in towns are ok, almost no rust . (Except those near sea)

2. Cars that been driven regularly on motorways tend to get more rust however if used daily they got washed from the rain water in the next few days of use therefore not that bad here. 

3. The worst category is the cars that hasn’t been used everyday but regularly been taken on short motorway trips then immediately left to stay stationary for days. So what happens then: car picks a lots of salt and grit from the road, since it’s been on motorway at higher speeds that mixture of salt +grit+water covers entire car including underbody and engine bay, it’s like you were driving through the sea. Then the car been parked until next weekend ideal conditions for forming a rust on all possible places ., especially those parts that are not properly protected. 
4. Accident repaired cars- once the original body work been reworked the rust is only a matter of time and will show up much faster than if the car was original. , the reason why Toyota and all others may refuse any warranty if they notice any bodywork repair done, unless been carried out by official dealer. 

[stantheman1]

^^ I totally agree but like to add to the list - Driving on newly  'surface dressed' roads at speeds greater than 10mph as the loose chippings do their best to compromise the unprotected areas underneath, then when driven over gritted roads exacerbates the problem.   

[Madasafish]

Our D4D Yaris is now 18 years old. We bought it at three years old.

I am fortunate to have a pit in our garage and every three or so years inspect the underneath for corrosion. And Waxoil/Dintrol the affectd bits.

Recently the paint round the rear suspension mounts to the body has been peeling so a quick scrape of any flakes and more Black Waxoil. Also the inner sills running from front to rear wheelarches.

I also repaint the exhaust with heatproof paint every so often..

[stantheman1]

I stopped using Waxoyl on the suspension components for the reasons you mention, I was gutted to find the black paint peeling on the edges of the wishbones etc on the cars that I had from new after only a couple of years. I have now been using silicone spray for the last 20 years to protect the painted components (after being cleaned down) twice a year to great effect. I still use Waxoyl in other areas such as the doors and box sections etc but I am 100% certain it was the Waxoyl that caused the peeling as I have not seen it since.

I've been using Waxoyl since the early eighties when it first appeared on the market, you could only purchase it in gallon/5 ltr metal containers iirc it was made by Finnigans, I used it to revive old underseal by brushing over with Waxoyl.

[Roy124]

On 2/26/2020 at 8:58 PM, wildtapholer said:

You never said which part of the country you bought the car from, my wife's first Yaris I bought her was from a garage at Scarbrough and suffered the same fate, red rust underneath due to the salt on the coastal roads, I just changed the engine oil and put it through a spray gun and sprayed it under the car, when all the dirt from the road collects on it, it gives a nice water proof coat once all the dirts built up. 

I was going to say just this.  I had a rust bucket car (OK they all had a reputation those years) from Kings Lynn.  My next model was much improved and from Birmingham.  My garage (near the east coast) said you could tell immediately that it was an inland car.

[Madasafish]

I would add to the above, It was obvious to me when we bought the Yaris in 2005 that the petrol filler pipes would rust being exposed to grit in the rear wheelarch so I cleaned and undersealed them in 2006, regularly clean the wheelarches with a hose and black  waxoil as needed.

 

The rear suspension cross beam is rust free.