Toyota Faulty Valve Springs Recall List Announced

Toyota had just managed to settle the recall waters a little bit last month, when its premium division Lexus debuted a recall for 17,000 HS 250h hybrid vehicles that were suspected of having a fuel leak problem. Subsequently, the company tried to push the public opinion calm pedal again, as its UK division issued a release stating that it had solved 95 percent of the mammoth accelerating issues recall campaign. But that was just the calm before the storm. On July 1, Toyota announced that 270,000 vehicles sold around the world, out of which 180,000 outside Japan might experience a powerplant problem that would cause their engines to stop while they are in motion. The list of affected models included multiple Lexus sedans and the Toyota Crown model sold on the automaker’s domestic market. The vehicles might use faulty valve springs, which can break, causing engine vibration, stalling and even serious damage to the powerplant. The automotive producer didn’t make things clear at the time, neither regarding the cause nor the solution of the problem, only saying that it was considering different options to solve it. A few days later, Lexus announced that it will debut a recall for the 138,000 affected models in the U.S. The company also informed us that the problem had been caused by certain particles that contaminated the valve springs during the production process. The issue affects the carmaker’s 3.5 liter V6 engine, as well as 4.6 liter and 5.0 liter V8 powerplants, built between July 2005 and August 2008. Toyota said it would replace all the valve springs with redesigned ones free of charge. Toyota’s UK made the headlines again, announcing that the recall fix operation has a duration of between 7 and 22 hours (depending on the model) and that owners of the affected Lexus models will receive a replacement vehicle for the period in which their car is being serviced. A Toyota press release issued after that indicated that the 270,000 affected vehicles are spread as follows: 138,000 in the U.S, 15,000 in Europe, 10,000 in the Middle East, 6,000 in China, 4,000 in Canada and 8,000 in other regions, including South Africa. The report also showed that the company will recall 91,903 cars in Japan due to the faulty valve springs issue. Subsequently, Toyota officials confirmed that the company had known about the faulty valve springs issue for a few years, but chose not to debut a recall as it considered that it wasn’t the case. The official added that the Toyota had decided to change the valve spring part in order to prevent the problem from spreading any further. Now, the official papers of the Lexus USA recall have surfaced the web (thanks to lexusenthusiast), allowing us to see the complete list of details. The document offers the detailed list of affected models (complete with model year, VIN and production period), which you can see in the adjacent image, as well as a timeline that describes Toyota’s discovery of the valve spring issue. You can download the full document (PDF format) following the link after the jump. We can also see that the faulty valve springs have been manufactured by the Japanese TOGO SEISAKUSYO Corporation. The official story begins in the March 2007-September 2007 period.
Toyota received a technical report from its domestic market that showed an abnormal level of noise and vibration for the engine start-up phase. The company’s investigations reveled that the engine valve springs had broken. A foreign material (Zirconia) was discovered at the starting point of the breakage, with the fracture surface appearing to be resulted from fatigue. It was presumed that Zirconia applied to the surface of the part’s casting furnace wall could be peeling off and mixing with the spring material. As a result, the casting furnace was modified in September 2007.

October 2007-December 2007

New broken valve springs investigations revealed that silicone oxide was found at the starting point of the breakage. The material is a by-product of a secondary refining process, which is (in theory) eliminated during the manufacturing process. As the effect of residual silicon oxide on the strength of the spring was not clear, new investigations were opened.

January 2008-August 2008

Toyota concluded that the valve spring strength was not likely to be affected by the aforementioned foreign material’s introduction during the production process. However, considering that it is impossible to perfectly control the foreign material contamination during the production process of the valve spring, Toyota changed the wire diameter of the valve spring from 3.3mm to 3.4mm in August 2008, also continuing to monitor field reports. The company received a relatively small number of broken valve spring reports, with the majority of them reporting abnormal engine noise, rough unit performance and no start conditions that were clearly noticeable to drivers.

September 2008-September 2009

Toyota continued monitoring field reports and investigating the effect of silicon oxide on the strength of the part. As an additional safety measure, the company increased the wire diameter of the spring again, bringing it from 3.4mm to 3.5mm is September 2009.

October 2009-June 2010

Toyota carried on with the aforementioned measures. Even though the company did not receive any reports indicating crashes or injuries related to the issue, the number of reports of broken 3.3mm diameter valve springs produced by August 2008 increased, with the number of reports of total engine failure following the same trend. The investigation showed that the valve springs using a wire diameter of 3.3mm could be affected by a micro-foreign object in the material, eventually breaking. In addition to that, it was confirmed that the valve spring with a wire diameter of more than 3.4mm are strong enough to correct the problem.

July 1, 2010

Toyota decided to debut a voluntary recall for all vehicles equipped with the aforementioned 3.3mm diameter valve spring within the affected range. The campaign will also be conducted in Japan Canada, Australia, Europe and other countries.

The company has not released the estimated number of vehicles actually affected by the problem. Toyota previously said that that there is a 0.2 percent chance that a vehicle actually experiences a malfunction due to the problem. Recall campaign instructions sent to the dealers (published by Jalopnik) shows that owners of the affected vehicles will be notified when the replacement springs become available, in late July. Various media reports indicated that the recall campaign could take a financial toll of $230 million.

Our say: Toyota is reinventing the valve spring but this should be a step towards reinventing the quality of its vehicles.
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 Download: Lexus U.S. Faulty Valve Springs Recall (PDF)

About the author: Andrei Tutu
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In his quest to bring you the most impressive automotive creations, Andrei relies on learning as a superpower. There's quite a bit of room in the garage that is this aficionado's heart, so factory-condition classics and widebody contraptions with turbos poking through the hood can peacefully coexist.
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