My Riviera has 114,000 miles and I started noticing engine noise about 6-8 months ago. I took it to a mechanic for oil change and diagnostics. He told me that everything checked out okay but the turbocharger was making a "growling" noise. How will I know if this becomes a major problem? What will the engine act like? Thinking of trading cars and wondering what kind of negative this will make in trade-in value?? boo hoo Thanks for any input!!

Are you sure it is a turbocharger and not a supercharger? Because almost all riviera's that came with any "charger" options came with the supercharger. If it is the supercharger then the growling your mechanic was hearing was the bearings in the supercharger. The bearings are going out due to lack of maintainence. The oil inside the supercharger must be changed every 50,000 miles in order to keep your supercharger running at optimal proformance. So what you are going to have to do is replace the bearing and oil otherwise the supercharger will freeze up and possibly cause major engine damage. But if it is the turbo charger then it is still the bearings, but I dont think there is any oil in the unit. They are just sealed bearings and eventually they just dry out because of the high temps from the exhaust gases. (the supercharger is connected via a belt and is ran by the engine itself, and the turbocharger is ran by exhaust gases and doesn't kick in until the pressure gets so high or you reach certain speeds)

I'm guessing the original person who posted this question has solved the problem, but for all others, beware the supercharger problem, there have been cases where lack of maintenance will cause MAJOR engine problems, such as mixing coolant and oil, and need for complete reconstruction of engine