1996 Volvo 850 Turbo Sedan with 110,000 miles. This has just happened over the course of the last week, hoping someone can help me out. My car is starting to blow out white smoke from the exhaust when I get on the highway, only after I get on it and the turbo needle goes in the white. Then when I let off the gas and the turbo needle goes to the black, a puff of white smoke comes out of the back of the car.

I used to use Mobil 1 5w30 per the Volvo Dealer in Hartford, CT. They said Volvo Corporate changed it from 10w30 to 5w30 in a new service bulletin about a year ago. Last week I did an oil change, put it back to 10w30 Mobil 1. (I read on here that the 5w30 is too thin and gets past the turbo seals).

I also spot some light oil around the waste gate area.

One friend said maybe I put too much oil back in after oil change, but I checked last night and the dipstick is at about 80%.

Any suggestions would be greatly appreciated! Thanks for the help in advance.
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1989 240DL B230F w/ 223k miles. Stock, except for some Virgo's and my stereo.