Turbo & oil supply
Catted up-pipe breaking up and damaging the turbo
The 2005–2006 XT has a small catalyst inside the up-pipe between the headers and the turbo. When its substrate breaks apart the pieces go straight into the turbine wheel, and the dust can clog the downstream converter.
Frequency basis: Two owners in one 2020 thread had the up-pipe catalyst disintegrate (one also clogged the rear cat); a 2011 thread calls the up-pipe cat a bigger worry than the turbo bearings. Only 2005–2006 cars have the catalyst in the up-pipe, so the exposure is specific to this model year.
Symptoms
- Sudden loss of boost with a rattling or grinding noise from the turbo
- Chipped or broken turbine (hot-side) blades found when the turbo is pulled
- Loss of power with the rear cat glowing or restricted; P0420 can appear afterwards
- Dealer quotes of about $2,700 for the converter alone
Causes found
- Heat cycling and age break up the ceramic substrate in the up-pipe catalyst
- Misfires or rich running from other faults overheat the catalyst and speed up the breakup
Check in this order
- With the downpipe off, inspect the turbine wheel for broken fins and shine a light up the up-pipe for loose substrate
- After any turbo failure, decide which came first: cat debris damages the hot side, oil starvation damages the bearing
- Check for metal in the banjo screens and do a compression test before paying for a turbo
What fixed it
- Replace the up-pipe with a catless unit when the turbo is replaced (about $50–100 for a pipe); this is the near-universal forum recommendation but it affects emissions compliance, and the ECU may need a tune or the EGT-sensor resistor mod
- Replace the downstream converter if it was clogged by debris; aftermarket catted front pipes were reported at $150–180 versus the $2,700 dealer quote
- Rebuilt or new turbo plus catted downpipe and a stage-2 tune was one member's recommended package after a failure
References on this site
OEM parts
- 44101FE070Joint pipe assembly, exhaust front (up-pipe)
- 44022AA150Gasket, exhaust turbo inlet
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.
- 1.2005 Outback XT with blown turbo and bad cat
subaruoutback.org · Forum thread · 2020, 7 posters, two cat disintegrations
- 2.Outback XT stock turbo reliability
subaruoutback.org · Forum thread · 2011: "the cat up pipe is more of a concern than the potential bearing failure"
- 3.Clogged catalytic converter problem
nasioc.com · Forum thread
- 4.A Guide to Replacing the Catalytic Converter on Your 2005-2010 Subaru Outback
go-parts.com · Article · vendor guide; P0420 does not by itself mean the converter is bad