It would help if you would specify year and engine. All of the 4 cylinder 2.5 liter 4 cylinder engines use 4.2 US quarts.
4.4=0
5w-30
My 1997 legacy gt sedan takes 4.8 quarts of oil.
15w/40w synthetic
o2 subaru
1997 subaru impreza consume 5.8 litres of oil
5w30
It takes 6.9 qts of oil.
Is the oil leaking and hitting exhaust? if so it is the o-ring in the oil pump. Subaru is known for that!
4.2 quarts
As per the Subaru Legacy Service Manual: 5.5 Liters, 5.8 US qt or 4.8 Imp qt...
A 2002 Subaru Legacy uses standard 10w-30 weight motor oil. During the winter, a lighter weight oil may be desirable in particularly harsh locations.