Cautionary Turbo Tale


Patrick McAneny
 

Several months ago my engine lost performance , it would not exceed 1800 rpm. I have a Volvo TMD 22A and normally could get it up to 3000 rpm. I discovered that the turbine did not spin easily and assumed it was the result of running it slowly and a build up of carbon. Today , I took the turbo off and brought it home , while trying to explain how a turbo works to my wife and pointing to where the air enters the turbo , she innocently asked me, Is that supposed to be there? When I looked , I could not believe it, there was a tightly wound  wad of paper towel sucked tightly up against the turbine. I don't know how any air got passed it. I must have left a paper towel in the engine room and it got sucked up through the filter , which is not a proper filter at all . There is a black plastic housing in where I would expect a filter to be , but it is empty . I will now place a wide mesh screen over the opening. This explains the gray smoke , and some black smoke I never had before , not enough air. I also discovered oil in the tube connected to the intake manifold , not good , I assume the turbo has a bad seal . Needless to say, its going in  for a rebuild. So keep track of those paper towels , and save your turbo !

Happy Thanksgiving Pilgrims ,

Pat & Diane,

SM Shenanigans


Duane Siegfri
 

Pat,

Please check on what I'm about to write yourself since I'm not much of a mechanic.  

Oil in the Intercooler Air Duct is not necessarily an indication of an oil leak in the Turbo.  On my Yanmar there is a breather tube connected to the valve cover and to the air filter.  The intent is that when pressure in the crankcase increases it is relieved by the breather tube.  Pressure is caused by heat increasing the air pressure inside the crankcase, but mostly from "blow by", which are the gases that leak out of the combustion chamber.  

These gasses contains some hydrocarbons, and instead of letting it drip under the engine the tube directs it to the air intake.  If there is a lot of oil, that's not a good thing.  If there is some evidence of oil streaking, or the intercooler is a bit wet with oil, that's normal.  The amount of "blow by" is proportional to the condition of the piston rings, valve seats, etc.  A worn out engine will have more "blow by" than a new one.

Of course, it could also be an oil leak in the turbo...

Duane
Wanderer, SM#477