I have a 2001 Subaru Outback Sedan that recently had an engine swap about a month ago. The newer engine has about 150K miles on it, while the body has about 240K. There seems to be an oil leak somewhere towards the passenger side and is leaking onto the exhaust. The previous owner persisted that there weren’t any leaks anywhere, and on the hour long drive and for about 4 days of sitting there was no leakage, but then began apparent. Any thoughts on what or where the leak could be and how much would it cost to repair?
Oil leaks can come from anywhere, but a typical leak point on that engine is the head gasket at the right front, just above the oil filter and just forward of the exhaust pipe. The oil then leaks out and hits the exhaust pipe.
You say this car just had an engine swapped with one with 150K miles? To install a used Subaru engine without replacing the head gaskets first is crazy. That is a known and predictable failure item. To replace them now requires removing the engine again. That job runs anywhere from $2200-$2800 around here.
First do a visual inspection, see if you can see where it is leaking. If nothing obvious, clean the engine off and check it every day for signs of oil that wasn’t there the day before. The next step is to add some dye to the oil, and us a UV light to see where it is leaking. Until you know where the leak is, no way to fix it. Possibilities betsides the head gasket idea above are valve cover gaskets and camshaft or crankshafts seals. Power steering fluid or transmission fluid are also possible sources.