Here is just a bit of inside information to help you better understand the used car dealers inventory.  Most used car dealers buy their inventory from auctions.  If the dealer doesn't know the mechanics of vehicles very well chances are their cars will show it.

After a dealer buys a car from an auction they have an opportunity to put the vehicle in PSI (post sale inspection) which cost the dealer an extra fee.  For those dealers who are cheap and want to save the extra $90 fee take a gamble.

Imperial Capital Cars puts every vehicle through PSI and if there is a fail for any reason the purchase is void.

For future reference ask your dealer if their vehicle pass PSI at the auctions they buy from.  Im sure the dealer will be surprised you even know what PSI is.