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760 Turbo blowing white smoke, BIG Time! 700

The '86 760 Turbo I've been working on is blowing white smoke like a mosquito fogger. I've been working on the vehicle, finally getting it running last week. I drove it back and forth to work all week. It's about 15 miles each way. Friday afternoon I took it for a test drive, going about 50 miles on the interstate. Shortly after getting off the interstate, when stopping for a Stop sign, I noticed there was white smoke behind the wagon. After going another 7 miles or so, it was really smoking. In fact, the local police told me I couldn't drive on the streets with is smoking like it was.
At a local garage we found the exhaust to turbo discharge connection was loose. The back side of the turbo was covered with oil coming out of the exhaust. After tightening the exhaust header clamp, I was able to slip out of town and get the vehicle home.
Once home I disconnected the turbo to intercooler line. There was oil in this hose also. With oil coming out of both sides of the turbo, I began to think that the oil return line to the sump might be blocked. After removing this line I didn't find it blocked. It did have some build-up on the walls, but the line itself was not restricted.
The impeller does have some lateral movement but very little end-to-end movement. The impeller can be rotated by my finger through the discharge opening. It doesn't "spin" like flicking a pin-wheel, but it does rotate without any feeling of resistance.
Any thoughts?...information?...suggestions?
Ron








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    760 Turbo blowing white smoke, BIG Time! 700

    I had the same problem with my 90' 760. White smoke.. all the time. Put it in first gear, and watch the white smoke behind.

    It ended up being the turbo seals. I did the rebuild myself, found a rebuild kit for about $100 (just the seals for my mitsibushi turbo)

    Oil in the line from turbo to intercooler.. thats normal.. Just not in huge amounts.

    As for the oil feed line to the turbo.. most people recommend to replace and not clean.. as its the turbo's lifeline.

    Change the seals in the turbo.. not to hard, After that PULL the intercooler, tubes and throttle body and CLEAN it. You will be amazed at the crud in throttle body and will be amazed at how much better car will run.

    Hope thats of some help.

    tom
    --
    90 Volvo 760 Turbo, 86 Mercedes 300E,87 Maserati Biturbo,95 Hummer XLC








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      760 Turbo blowing white smoke, BIG Time! 700

      Tom,
      I'm inclined to believe its the oil seal in the Garrett turbo. I understand they use a labrinth type seal. I noticed that the smoke is heaviest (the vehicle is passing the most oil) when the engine is running at low rpms (idle). On the highway, 2,000 to 2,250 rpm, there was hardly any smoke. When I pulled the intake hose last night, I could turn the impeller but it really wasn't "free spinning". I couldn't flick it with my finger and send it spinning, it would turn as long as I applied pressure.
      Speculation. If the bearing(s) are gunked with oil deposits or otherwise bad, the turbo needs more force on the exhaust impeller to make it spin. At an idle there isn't enought exhaust pressure to spin the turbo. Without the turbo spinning the labrinth oil seals don't work. At highway speed the exhaust pressure is sufficient to spin the turbo. A spinning turbo allow the labrinth oil seal to function.
      Last night I pulled the oil return pipe (turbo to block), it's clear. I'm planning on pulling the turbo and inspecting the bearing(s). At this point I'm thinking a replacement of the bearing(s) should answer the problem. The supply oil hose and seals will also get replaced.
      Thank you for your input.
      Ron








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    760 Turbo blowing white smoke, BIG Time! 700

    I have always been under the impression that white smoke was a blown head gasket and black smoke was oil. Such has been the case with the terrible State-owned vehicles that have crapped out on me in the middle of now where.








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      760 Turbo blowing white smoke, BIG Time! 700

      My problem is not a head gasket, worn valve seals, or rings. There was oil dripping out of the turbo. For that much oil to get through the compustion chambers without burning would have fouled/flooded the spark plugs. I'm thinking that it's the oil seals in the turbo.








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      760 Turbo blowing white smoke, BIG Time! 700

      The head gasket went in my 1990 760 Turbo wagon, the smell of anti-freeze is unmistakable, the smoke as described is more like white vapor that dissapates rather than billowly white smoke that burning oil makes. Thats the difference than a little dark smoke coming from blow by in the clyinders.

      Jerry








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        760 Turbo blowing white smoke, BIG Time! 700

        My problem is not a head gasket, worn valve seals, or rings. There was oil dripping out of the turbo. For that much oil to get through the compustion chambers without burning would have fouled/flooded the spark plugs. I'm thinking that it's the oil seals in the turbo.







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