Bongo Fury

I last checked my coolant about two months ago when i toped it up( it was about half an inch low in the expansion tank) Ive done about 500 miles since checked it today and its on min is this normal loss through evaporation or do you think i have a small leak ?

definatley a leak, check all your hoses

If you can't see any obvious leaks, look for water/rusty stains as sometimes the coolant will hit a hot engine part and evaporate, so you don't notice a water drip, or a pool under the van.