You want to buy a used car from a dealer but car has lien on it what should you do?

You want to buy a used car from a dealer but car has lien on it what should you do?
I would be very leery to purchase anything from anybody while there's still a lien attached. As you probably know, this entitles the lien holder their right to however much was loaned against the vehicle, which must be cleared at the time of title transfer. The dealer should have taken care of this when they purchased the car from the prior owner.
Assuming the vehicle is worth pursuing, try making an arraignment with the dealer where they will allow you to accompany them to the lien holder's business, at which point the bill can be settled. Under no circumstances should you pay for the car without them first taking care of the lien.