Lexus Repair: blue smoke, recommended mechanics, 1996 lexus es300

Question
Jiffy Lube admits they overfilled my oil and left cap off. on my 1996 Lexus ES300 and now it is blowing blue smoke and smelling like burned oil under the hood.

I drove it 230 miles without knowing they had left cap off and over filled.

They said they have their own recommended mechanics who can fix the problem and said I
should   not Lexus  repair it because they would over charge me.

What could have they messed up?  

Answer
Hello, Lexus will not over charge you, they will in most cases charge you for a quality repair with quality mechanics. I would ask Jiffy Lube if their recommended mechanics have had factory Lexus training and if not what makes them qualified. What could have happened is either the piston rings are having problems or the valve guide seals.