GM to call back electric Volts over fire risk Bill Pugliano / Getty Images GM's electric Chevy Volt. General Motors plans to ask Volt owners to bring their electric cars into dealers to strengthen the structure around the batteries. The automaker said Thursday it plans enhancements to the vehicle's structure and battery coolant system to further protect the 400-pound lithium-ion battery from the possibility of an electrical fire occurring days or weeks after a severe crash. The enhancements come in response to a National Highway Traffic Safety Administration Preliminary Evaluation to examine post-severe crash battery performance. The move is similar to a recall and involves all the Volts sold in the U.S. in the past two years. The repair will take two to three hours to complete, Mark Reuss, GM's chief of North American operations, said. GM has built about 12,400 of the battery-powered Volts and sold about 8,000 of those. The call back comes after three batteries caught fire after side-impact crash tests done by federal safety regulators. The fires occurred seven days to three weeks after the tests and have been blamed on a coolant leak that caused an electrical short. No fires have broken out in real-world crashes. Volt customers will be individually notified when the modifications are available for their vehicles. The enhancements are being incorporated into the Volt manufacturing process as production resumes this month, GM said. Reuss said he was "optimistic" that the proposed Volt remedies would address NHTSA's concerns. According to the automaker, the modifications will: Strengthen an existing portion of the Volt's vehicle safety structure to further protect the battery pack in a severe side collision. Add a sensor in the reservoir of the battery coolant system to monitor coolant levels. Add a tamper-resistant bracket to the top of the battery coolant reservoir to help prevent potential coolant overfill. The repairs are a step below a formal recall. GM said it conducted four successful crash tests between Dec. 9 and 21 of Volts with the structural enhancement. The enhancement performed as intended and there was no intrusion into the battery pack and no coolant leakage in any of the tests, the automaker said in a statement. GM has made the Volt the symbol of its determination to seize a leadership position in fuel economy and green technology, and its engineers have been racing to respond to a safety investigation by U.S. regulators since late last year. "This remains a halo vehicle for us in technology and design," Reuss said. So far, battery cars coming up short