I recently took my 89 740 Turbo in because of billowing blue/gray smoke and for annual inspection. My repair man said it was a blown O2 sensor, which he replaced, and showed me the inspection report showing low emissions. The next day, the billowing smoke returned. He feels it could be a blown turbocharger, but isn't sure. This car is very low mileage (52,000). What else can I tell him to check and what is the likely cost if the turbocharger needs replacing? Anyone know a great Volvo repair place in Manhattan?

William, take of the hose connected to the turbo and stick your finger in there and make sure the turbine blade spins freely. If it does, your turbo is ok. You MUST go to Robert Lambie at Rawbear Performance in Clifton, NJ, ten miles outside manhattan. Take the Garden State Pkwy.

walk away from that yahoo of a mechanic.

I think your 02 was out because you are blowing oil out, maybe clogging up the sensor. Which (blowing oil) is very dangerous as it may suck all the oil right out of the engine, killing it instantly. Check your oil level.

Is there oil in your tail pipe?

The turbo people will tell how to check for bad turbo.

Original miles?