have 2002 s40 volvo 185,000
i use synthetic oli
well coouple of days ago on thursday added 3/4 of a litre of oil to my car as the oil was dirty...
next day it had a hard time starting like if it was choking when starting...
was thinking maybe added to much oil....finally got it started and ran normal to volvo where i got oil change...and this morning drove around and seems fine,,started fine...i read on the internet with too much oil added, it can wreck the engine,,pistons,,cylinders etc...
my ? is ,,would of the engine been wrecked by now or i just got lucky or maybe im paronoid
thanks

 

It would take a lot more than 1 quart to cause damage. People overfill oil levels all the time. If less than a quart, things should be ok. I wouldn't push more than that.

 

What where you hoping to achieve by adding extra oil?
I know a fellow volvo owner who went to the dealer to change the oil.They didnt drain the oil but filled the new on top of it.He had crazy smoking on the way home he went right back.I think he has blown some o-rings but it was some time ago cant remember.The point is the o-rings/seals will blow before the pistons get damaged but I wouldn't try my luck on this.
Just a funny fact.Every cabs in NYC are smoking badly.Reason is that what they do is checking the oil levels while the engine is running.Still non breaks pistons.
Funny fact #2:I knew a guy who worked at a shop and was told to top of the oil.What he did he actually filled the engine with oil completely all the way up to the cap.The engine didnt turn over it was locked.

 

I can tell you from experience that too much oil causes the crankshaft to "whip" the oil into a froth introducing air bubbles which causes a drop in oil pressure. This is where the problem lies, low oil pressure causing excessive wear. Since you had it serviced quickly after then I'd not worry about it.