Where is the error?

[Raimonds]

    My car - Subaru Forester Boxer, 2011, 2,0l, diesel, milage 230000 km ,EE20 - a red oil light came on in car's dashboard.  And  there was a slight noise coming from the engine. Oil was in level.Discovered in the service: wear of the main shaft at the first cylinder and wear of the engine piston rings. No defects were detected in the block and crankshaft. In the service, the engine crankshaft and the engine head were ground. The clutch, gaskets, oil have also been replaced. After repair, I drove 4000 km, the engine block and the engine broke. The service cannot explain why it happened. I did not participate in the rally. Maybe someone has had the same? Could it be possible thatafter aprecisely assembled engine, both the block and the engine itsself break? Maybe it's a riddle? 

 Raimonds.

[Mr B]

common issue on these is crankshafts snapping and depending on circumstances that can damage block halves around the bearings or beyond .
If rebuilding these ideally want use newest revision crankshaft and certainly no machine work to old fatigued crankshafts from known worse failure years of manufacture .
These 2008 to 2012 engines are difficult to deal with in terms of guaranteeing worth while outcome from a major overhaul .
Clutch plays huge role on torsional stresses crank gets so any replacement dual mass kit needs be ideally subaru oem or at least top spec oem manufacturer aftermarket parts .

Here most boxer diesels with major engine issues tend go to scrap as proper effort repair addressing all potential issues you can come across dealing with these is not cost effective & not a 100% perfect result guarantee ...
 

[Raimonds]

Thanks! I  thought so too. It's just that the service claimed that the engine and block were healthy before the repair. How can it be determined that the engine block and the engine are free of any defects? Or there is an instruments with which the measurements are taken? Or it is determined by looking and feeling?

And if these models havesuspected engine faults, I should consider getting a new short block rather than doing unnecessary repairs?

[Mr B]

Ideal scenario is newest superseding parts, in your case of total damage of block crank then short block good way go .
If block good then rebuild with newest crank design can be an option but block had redesigns and suspect flywheel/clutch and torsional damper has too .
The cranks tend fatigue so reusing the early model ones never seems good way go .
You can crack test & xray cranks but as the early ones known bad you best putting them straight in metal trash & going straight to better/new options .
Trouble is a good effort rebuild or replacement new short block is quite costly, you could look at pricing a used 2012 engine & do a long block swap ...