I have heard that putting sugar in my fuel tank may lead to my vans not working anymore. This is an outcome I am looking to avoid.

I use these vans to transport children, who I usually pick up from sites about a few miles out. I would be really miffed if those vans were disabled in such a way that they were not able to make it to those children.

Are there any other actions I should avoid taking with my vans? I really wouldn’t want to cause damage to them in such a way that they would fail before the children got inside them.