Engine
Oil leaks: valve cover gaskets, turbo oil lines, oil cooler o-ring
Oil on the passenger side of the engine that smells on short trips is almost always the valve cover gasket or spark plug tube seals dripping onto the up-pipe. The turbo oil feed and return lines and the oil cooler o-ring are the next suspects, and dealers have quoted head gaskets for what turned out to be several small leaks.
Frequency basis: Three or more owners with the identical passenger-side leak in one thread, separate 2018 threads for a 5MT XT and a Legacy GT dealer misdiagnosed as a head gasket, and valve cover gaskets listed as a top-four EJ255 problem. Expect it on any XT past 100k miles.
Symptoms
- Burning-oil smell after short trips, a few drops on the driveway, oil pooled in the "waffle" casting on top of the block
- A quart lost in 2,000–3,000 miles with no smoke
- Oil running down the back of the engine and onto the exhaust; smoke from under the hood at idle
- Dealer quotes of $2,000 for a head gasket or $6,500 for a reseal
Causes found
- Passenger-side valve cover gasket and spark plug tube seals (the most common finding)
- Turbo oil feed pipe fittings and the non-pressurised oil return hose, which cracks with age
- Oil cooler o-ring at the filter mount
- Crankcase breather hose by the PCV valve, and the oil pressure switch near the alternator
- Crossover pipe seals on top of the block leaking down the rear
Check in this order
- Degrease the engine, drive it, and find the source; UV dye helps
- Check the up-pipe and turbo heat shield for burnt oil: that pattern is a valve cover leak
- Inspect the turbo return hose and feed line fittings before anything else on the right side
- Do not accept a head gasket diagnosis for an external leak without a second opinion; the turbo engine's gaskets rarely leak externally
What fixed it
- Valve cover gaskets and spark plug tube seals, about $40 in parts for both sides; stopped the leak and the smell for several owners. The right side can be done in the car but is very tight; doing it with the timing belt is easier
- New turbo oil return hose and feed line seals
- Oil cooler o-ring (gasket 21370KA001)
- One owner with multiple small leaks chose to monitor rather than pay for a full reseal
References on this site
OEM parts
- 13293AA051Gasket, rocker (valve) cover
- 21370KA001Gasket, oil cooler
- 15192AA490Turbocharger oil tube
- 14423AA110Pipe complete, turbocharger
- 11852AA090Pipe, PCV
Parts diagrams
Factory manual chapters
Maintenance guides
Sources
Forum threads are owner reports, not factory findings. Counts are from the threads and complaint records read for this page; read the sources before buying parts.
- 1.05 XT Oil Leak - Pinpointing
subaruoutback.org · Forum thread · 2013–2021, 8 posters, 3+ with the same leak
- 2.05 XT limited 5sp oil leak?!
subaruoutback.org · Forum thread · 2018, 2005 XT 5MT, $6,500 dealer quote
- 3.'05 OB XT turbo oil leak...classic
legacygt.com · Forum thread · 2017–2018, head gasket quote overturned by a second dealer
- 4.Known Issues with 2005 Outback XT Limited???
subaruoutback.org · Forum thread · lists valve cover, turbo supply line and oil cooler o-ring leaks
- 5.4 Most Common Subaru EJ255 Engine Problems
8020automotive.com · Article