To avoid inheriting other people's debt/finance when buying a motor vehicle from a private seller, ALWAYS do a PPSR check. This check only costs $2 and it will tell you whether there is a security interest over the vehicle.
Unfortunately, we are aware of a few instances of people getting caught out in circumstances where they have bought a vehicle privately and the vehicle they've bought had finance attached. When the sale went through (ie funds were exchanged), the seller didn't clear the debt - leaving the buyer on the hook so to speak for that debt. Sometimes this doesn't become apparent until some time later - it's quite a shock and unfortunately, there is very little that can be done.
Visit here to access the check: PPSR - used car vehicle search.