2009 Scion xB. Had Mobil 1 15w50 oil in the sump. During a drive the cheap magnetic drain plug got lose and oil was lost. Took 4 quarts to get back to the full line on the dipstick, after replacing a drain plug. Oil that was added is STP 0w20. Oil filter still had almost 1qt of M1 15w50. This combination was in use for 7k miles with lots of stop&go and extensive idling.