Bullshit story. Impossible. Dad probably stopped at the local full serve and the attendant probably topped it for him. Engines are not wells, their is so many ways for oil to exit its not funny.
Putting ANYTHING into an S54 will guarantee rod bearing issues.This post ignores many details..
Depending on the engine, viscosity can be incredibly important. On the bmw s54 (specced for 10w-60) putting in 5w-30 will just about guarantee rod bearing issues.
I'm thinking more along the lines of a design miscalculation rather than a full-on flaw, as the oil passages that feed the heads are a little smaller than they should be, and it's hard to get thicker oils up to the heads, especially in colder weather.
If it's the 4 cylinder, it only holds about 3.5 quarts anyway, I think. Not a lot of oil for dirt tolerance.
The flash point of the oil was disturbingly low.
I wonder how long the spark plugs had been in? Or what the PCV system looked like...
That's not sludge, it's just grease. Somebody packed grease into the heads.Oil sludge is just myth.