I carried an unopened jug of antifreeze in my truck box. It stayed there for 7 years in the upright position. Eventually it leaked and soaked all the contents of the truckbox. I was pretty mad but it was my fault, it was there for too long and went unchecked. I packed it tight with other gear so it couldn't tip or rattle too much. But I think the other gear may have rubbed a hole through the container after all those miles. Just a FYI, even a sealed jug can lead to another SNAFU.