This week on Car Talk, the Great Haircut Debate continues, as listeners weigh on whether it's ethical to use a roadside McDonalds' restroom without buying anything.  On the automotive front, Ellen's mechanic says he can tell her Dodge Caravan is dying by the smell of its oil. Tom and Ray smell a conspiracy between the mechanic and Ellen's husband, who wants a new Volvo. Also, how a car's transmission is like the family dog; a book from 1922 might help fix Nikki's noisy Jeep; and on Stump the Chumps, we find out if John's sister duped him when she sold him his old VW Golf. All this and more, this week on Car Talk.