7 Reasons Your Vape is Auto Firing (Causes & Prevention) Just a heads up my vape started hissing, venting vapour and the mouthpiece got extremely hot for a few minutes. I wasn't using it at the time thankfully, but it did cause Exposing your vape to extreme temperatures is a fire risk. Avoid leaving it in a hot car or out in the freezing cold. Never use damaged, swollen or hot batteries. # One of my 18650 batteries is getting hot on its own I'm not using them and that I have checked it it lost half its charge without even using them : r Vaping