well i just dont get the whole "boiled oil" remark especially when the oil was synthetic...also stated the car was burning oil and now its running perfectly, makes no sense
Did you check the oil again after you left? Was it full then?
And the coolant was changed after the return? Replaced?
It is possible they never filled the oil up all the way. 6L is alot. Having low oil can cause the engine to run hot. Also, if the coolant wasnt flushed/filled right, it will cause overheating and bubbles. Wahtever they did sounds like they replaced it real quick and played it off cause they messed up. "Not coooool."