Toyota Sienna
3.5L V6 — Toyota's universal six-cylinder for midsize through SUV. Cam tower oil leak like the Tundra V8, but less common. Budget for water pump around 80k miles. Overall one of the most reliable V6 engines on the market, 250k+ mile lifespans documented.
Sienna XL20 V6 3.5 — more power, same door issues
266 hp V6 from 2007: significantly stronger. Sliding door issues remain. Engine one of the most reliable Toyota V6s.
Engine Weaknesses 3
RTV sealant at cam tower ages. Same issue as Toyota V8 engines, less common on V6.
Symptoms: Oil smell, oil trail at front of engine
Water pump with plastic impeller wears out. Replace during timing belt/chain service.
Symptoms: Coolant loss, drip under engine
Slightly elevated oil consumption at higher mileage — normal for the series. Regular monitoring sufficient.
Symptoms: Oil level drops between changes
Vehicle Weaknesses 1
Wiring in door mechanism frays, lock motors fail. Toyota extended warranty to 9 years/120k miles for 2004-2010. Affects very many vehicles.
Reports & Tests
5377 owner complaints filed with NHTSA (2004–2010). Most reported: Body Structure (2094), Latches & Locks (557), Airbags (475).