Laguna Hills, CA – November 13, 2018 – Subaru of America, Inc. (Subaru) is recalling certain 2012-2014 Subaru Impreza, 2012-2013 Impreza Stationwagon, 2013 Subaru BRZ, XV Crosstrek and Toyota Scion FR-S vehicles for a valve spring issue that could cause engine stall. This recall is expected to affect 165,534 Subaru vehicles in North America.
According to the NHTSA Recall Safety Report, due to an improper design of the valve train within the engine, an excessive stress is generated on the valve spring compared to the design condition. In addition, a very small amount of the impurity within the composition of the spring material is not avoidable in the manufacturing process. The combination of excessive stress and the dispersion of the impurity in the valve material during manufacturing may cause the valve springs located inside the engine of the affected vehicles may fracture, which may cause engine malfunction. In the worst case, the engine may stall during driving, and restarting will not be possible, increasing the risk of a crash. Drivers may have a short window of advance warning as abnormal noise or vibration may occur prior to the engine stalling.
Timeline of Events
In April of 2012, SUBARU CORPORATION (Subaru) received a technical report from the Japan market which described an abnormal noise and rough idling. The collected engine was examined, and it was surmised that the valve spring broke and fell off, making contact with the piston and causing a rough idling and an abnormal noise. While a component analysis was conducted, no spring material flaw was identified and the cause of the fracture was unknown. In May 2013, the lower limit of the tolerance of the spring wire diameter was raised as a precaution and in response to eleven technical reports related to stalling reported from the U.S. In August 2016, based on additional examinations of engines collected from the field, it was determined that a ndactor not avoidable in the manufacturing process, namely very small amount of impurity within the composition of the spring material, could affect spring fracture.
Three additional technical reports related to stalling were issued from the U.S. during this time frame, but by September 2018 it was determined that a higher occurrence rate than estimated with general manufacturing dispersion from the vehicle manufactured with lower spring tolerance. Further investigation led to the revelation due to the improper design of the valve train, stress generated exceeded the design condition, and, when combined with the dispersion of impurity within the composition of the spring material, could cause spring fracture due to fatigue. On Oct 25, 2018, Subaru issued a safety recall for vehicles equipped with a similar valve train design manufactured prior to the tolerance adjustments made in May 2013.
Subaru will notify owners, and all valve springs will be replaced with new ones free of charge. Owner notification will occur within 60 days of Dealer notification, which began on November 1. If parts are not available by that time, owners will be notified that parts are not available yet and they will be re-notified once parts are available. Owners may also call the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153). The NHTSA Campaign Number for this recall is 18V-772.