Overview of Toyota’s stance on excessive oil consumption in the 2AZ‑FE, affected years, historical warranty enhancement (now expired), and a field‑tested mitigation procedure.
Summary
Toyota acknowledged that some vehicles equipped with the 2AZ‑FE 2.4‑liter 4‑cylinder could exhibit excessive engine oil consumption. The company outlined a sealed oil‑consumption test and repair paths in technical bulletins and a past Warranty Enhancement Program (ZE7). While normal oil use is expected in any engine, consumption beyond Toyota’s test threshold was considered excessive and, when verified, was eligible for remediation during the program’s active period.
Toyota’s Official Stance
Excess oil use may occur due to ring sticking and oil drain‑back hole coking in certain operating conditions.
Diagnosis relied on a sealed oil‑consumption test (fill to FULL, seal, drive a specified distance, measure loss).
Within Toyota documentation, only consumption above a defined threshold qualified as “excessive.”
Repairs for confirmed cases were handled as a customer satisfaction action, not a safety recall.
Model Years Affected (ZE7)
The ZE7 warranty enhancement focused on models using the 2AZ‑FE. Key coverage examples:
Camry: 2007–2009
Camry Hybrid: 2007–2011
Camry Solara: 2007–2008
Corolla: 2009–2011
Corolla Matrix: 2009–2013
RAV4: 2006–2008
Scion tC: 2007–2010
Scion xB: 2008–2015
Note: Coverage varied by VIN and market; always verify against the original bulletin language for exact eligibility.
Warranty Enhancement (ZE7) — Historical Reference
Primary phase: through late 2016 (time‑limited campaign window).
Secondary phase: up to 10 years from first use or 150,000 miles, whichever occurred first.
Vehicles had to pass the official oil‑consumption test to qualify for parts replacement.
As of 2025, ZE7 is fully expired and no longer provides coverage; this information is kept for context.
Owner’s Note
Oil use began after ~160k miles (2019), ramping to about 1 qt / 600 miles in easy driving and 1 qt / 300 miles in mountain driving with engine braking—outside ZE7 coverage by then. After a ring‑soak procedure (below), consumption improved to roughly 1 qt / 2500 miles.
Mitigation Procedure: Ring Soak with Berryman B‑12
Read First — Important Safety
Fire/chemical hazard: B‑12 is a very strong, highly volatile solvent. Use nitrile gloves, eye protection, and excellent ventilation. Keep away from paint and plastics. Store out of reach of children.
Hydrolock risk:Any liquid left in cylinders can destroy an engine. Follow the evacuation steps carefully.
Do at your own risk: This is an owner‑devised mitigation, not an official Toyota repair. If unsure, consult a professional.
What You’ll Need
Berryman B‑12 Chemtool (1 can)
Basic hand tools to remove engine cover, ignition coils, and spark plugs
Funnel suitable for spark plug holes
Shop vacuum with a narrow metal or thick plastic straw/tube adaptor
Light oil for temporary cylinder lubrication
Fresh engine oil and a new filter
Protective gear: gloves, eye protection; rags; catch pan
Step‑by‑Step
Prep: Engine must be fully cool. Disconnect the negative battery cable to prevent starts. Remove engine cover and coils with care (brittle plastics). Blow away debris around plugs.
Remove plugs and, using a funnel, pour about 1/8 can of B‑12 into each cylinder. Thread the plugs back in lightly (just a few turns) as dust caps.
Soak (Night 1): Leave overnight.
Top‑up (Morning 2): Remove plugs, distribute the remaining B‑12 across all four cylinders. Re‑install plugs lightly.
Soak (Night 2): Leave overnight again.
Evacuate: Remove plugs. Use the shop‑vac with straw adaptor to extract as much liquid as possible from each cylinder. Expect some solvent to have drained into the crankcase.
Relubricate: Add a generous splash of light oil to each cylinder. Wait a couple of hours, then vacuum the oil back out thoroughly.
Clear the cylinders: With plugs still out, reconnect battery. Place a thick rag over the plug wells and crank the engine briefly to expel any remaining mist/liquid. Verify bores are dry.
Reassemble: Install spark plugs and coils. Do not over‑torque plugs—threads are lubricated; aim for snug and secure.
Change oil & filter: Mandatory. The solvent that seeped past rings has contaminated the crankcase.
Restart: Extended cranking and visible smoke are normal initially. Let idle several minutes, then drive gently, followed by some higher‑rpm runs and engine‑braking to help rings reseat.
Results
Many owners report substantial reduction in consumption when ring sticking is the root cause. Track usage over several fuel tanks; improvements often stabilize after a few hundred miles.