Curious on how they found the problem? The 2022-2023 Toyota Tundra engine recall investigation spanned over two years and involved numerous good and bad engines.
In case you haven’t heard of this recall, it affects more than 100,000 2022-2023 Toyota Tundra and Lexus LX 600 all with gas engines, not hybrid. These engines were built in either the Tahara, Japan, or Huntsville, Alabama engine plants. Toyota says machine debris was found in those engines causing engine failure.
The investigation details are from a Defect Information Report posted to NHTSA.gov and included with the recall notice.
[Related content: 2022-2023 Toyota Tundra recall for engine failure affects 100k trucks]
Toyota Tundra engine recall investigation
The defect reports states the problem and the steps they took to correct it. This information below is copied and pasted from the report:
Description of Problem
The subject vehicles are equipped with a specific V35A engine that contains crankshaft main bearings which allow the crankshaft to rotate within the engine assembly while running. During a specific production period, there is a possibility that engine machining debris of a particular size and amount may not have been cleared from the engine during manufacturing and subsequently contaminated the engine assembly during the production process. For these engines in the subject vehicles, the pressure on the main bearings due to the engine configuration is such that, if the aforementioned machining debris adheres to the bearings and operation of the engine continues at higher loads over time, failure of the bearings may occur. This can lead to potential engine knocking, engine rough running, engine no start and/or an engine stall. In the subject vehicles, an engine stall while driving leads to a loss of motive power. A vehicle loss of motive power while driving at higher speeds can increase the risk of a crash.
Chronology of Principal Events
March 2022 – December 2022
In early March 2022, Toyota received a field report that indicated a vehicle equipped with a V35A engine stalled. Toyota recovered the involved parts and performed an investigation of the engine failure. Through this investigation, it was found that the crankshaft main bearings had seized. In late July 2022, a Toyota field report and a dealer report were received that alleged the failure of two different V35A engines with damaged bearings. Toyota recovered the involved parts and performed an investigation of the engine failures. Through this investigation, it was found that the crankshaft main bearings had been damaged, but due to the nature of the failures, Toyota could not determine the cause of the damage. Toyota hypothesized that debris could be present from the engine machining process. To reduce the possibility of engine contamination during manufacturing, Toyota implemented cleanliness process changes at its engine manufacturing plants.
January 2023 – August 2023
After cleanliness process changes were implemented, Toyota continued to monitor the market for any increase in trend related to the issue. During this time, Toyota also recovered V35A parts alleged to contain engine contamination to confirm the adequacy of the manufacturing process changes. September 2023 – January 2024 Toyota observed an increase in dealer and Toyota field reports related to engine failure involving debris. In mid-October, Toyota began an investigation into the design validation process of the V35A engine and the installation validation process of the engine manufacturing equipment. It also continued to assess the effectiveness of manufacturing process changes implemented earlier. Toyota also continued to recover V35A engines from the field. Toyota used these engines to inspect the oil filters and engine parts for debris. Toyota also used these engines to study the effect of debris in the engine over time. As part of its investigation into the design validation process of the V35A engine, in November 2023, Toyota began analyzing the bearing durability studies that were performed during the development of the V35A engine. In January 2024, the Alabama engine manufacturing plant was requested to provide all quality testing swatches used to capture debris samples at specified intervals dating back to the beginning of production of the V35A engine for analysis. These samples represented the size and amount of debris present for production periods, or lots, of engines. In January 2024, Toyota presented the status of the ongoing investigation items to NHTSA.
February 2024 – May 2024
As a part of its investigation into recovered parts from V35A engines, in February 2024, Toyota began collecting and tearing down good engines recovered from the field. Toyota used these engines to analyze the oil for metal content and to perform an inspection of the oil passages. Toyota noted that certain recovered engines showed some levels of bearing degradation or damage but had not shown signs of failure. These bearings were sent to Toyota’s engine design teams in Japan for further analysis. The bearing durability studies were completed in March 2024. From these studies, maximum operation stress during driving, stress limits of each bearing, and size of debris that each bearing was designed to withstand under normal loading were identified. In early March 2024, Toyota began scanning the testing swatch samples which were collected from the Alabama engine manufacturing plant for further analysis. In late March 2024, Toyota presented an update of the status of the ongoing investigation items to NHTSA. In early May 2024, the analysis that was being performed on bearings recovered from good V35A engines was completed. The results showed that the damage that was seen on the bearings was from debris created during the engine machining process, and that there were sufficient debris sizes and amounts present to cause a bearing to fail. Toyota also finished its scanning and analysis of testing swatch samples from the Alabama manufacturing plant. A statistical study was applied to the data to create probability models. Based on the results of the above investigation, Toyota determined that during a specific production period, there is a possibility that engine machining debris of a particular size and amount may not have been cleared from the engine during manufacturing and subsequently contaminated the engine assembly during the production process. For these engines in the subject vehicles, if the aforementioned machining debris adheres to the bearings and operation of the engine continues at higher loads over time, failure of the bearings may occur. This can lead to potential engine knocking, engine rough running, engine no start and/or an engine stall. In the subject vehicles, an engine stall while driving leads to a loss of motive power. A vehicle loss of motive power while driving at higher speeds can increase the risk of a crash.
May 23, 2024
Toyota decided to conduct a voluntary safety recall campaign. As of May 20, 2024, based on a diligent review of records, Toyota’s best engineering judgement is that there are 166 Toyota Field Technical Reports and 824 warranty claims on the engines in the subject vehicles that have been received from U.S. sources that relate or may relate to this condition and which were considered in the decision to submit this report.
Description of Corrective Repair Action
All known owners of the subject vehicles will be informed that remedy is under investigation and that they will be contacted when further information is available.
The bottom line
Frustrated owners demand the problem gets fixed right away, however, as you read above, fixing the problem takes much longer than people realize. This is a fascinating look into how manufacturers do detective work to find, validate and ultimately fix a problem.
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