 During December 2011 , GM conducted four crash tests of Volts with the reinforced steel and upgraded cooling system , resulting in no intrusion to the battery and no coolant leakage . On December 22 , 2011 , the NHTSA also subjected a modified Volt to the same test that led to the original fire , with no signs of the damage that is believed to have been the cause . The NHTSA said “ the preliminary results of the crash test indicate the remedy proposed by General Motors today should address the issue of battery intrusion ” though its investigation remained open . General Motors declined to say how much the modifications would cost . 
