So a friend of a friend has a 2.0L Holden Vectra, has had an oil leak for quite some time and made a road trip to Wanganui last week. Before she left to head home, she topped up the oil. About 5 minutes into the return trip it stared billowing "white" smoke so she pulled over and got it towed back to town, and got a flight home as she had to be at work the next day. Yesterday, after it being towed back from the tow yard (also an auto wrecker) to the friends house, I went and had a look. She was told the towies "mechanic" has checked it out and it had a "blown piston".
First thing I did after hearing about the topping up of the oil and the white smoke was pull the dipstick. It was half full, not half full on the measuring part, but half way up the dipstick! I started it for about 5 seconds to confirm the "blown piston" diagnosis. It ran smoothly on all four so that diagnosis is BS, and didn't smoke at all in the few seconds I had it running.
It was dark and cold so didn't try solve anything on the spot, but other than sounding sluggish while turning over and a littlle "choked" while idling, which I would expect from something with ~4l too much oil, everything seemed sweet.
Google has all sorts of advise as to what damage could have been done, but does anybody have first hand experience about what long term damage could have been done? My next plan is to drain it and refill with the right amount and see what happens.