Hello, Ricki-Ellen,?
Puddles, drips (that smell like coolant, sweet) under van?
Coolant odor inside van?
Discoloration on coolant hoses or at lower radiator fittings or radiator body?
Loose coolant hoses or bulging hoses? Loose hose clamps?
Coolant overflow tank stained w/coolant? possibly cracked
Moderate white smoke from exhaust? -- coolant leaking into engine
Performance issues?
How long has this been happening (what is "very gradually"?
When weather hot? Cold(er)?
When engine hot (after a long drive e.g.)?
Any recent work performed on your vehicle?
Last maintenace?