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Washington · Article Updated May 24, 2026

Engine Defects Under Washington Lemon Law

Engine failures, stalling, misfires, oil consumption, and other engine defects that qualify under RCW 19.118.021's substantial-impairment test.

Engine defects are among the most common bases for Washington Lemon Law claims. Most engine failures qualify under the RCW 19.118.021 substantial-impairment test — and many qualify as serious safety defects under RCW 19.118.041(1)(b), triggering the lower two-attempt threshold.

Common qualifying engine defects

  • Stalling — often a serious safety defect (loss of vehicle control).
  • Misfires — substantial impairment of use; can be safety defect at speed.
  • Excessive oil consumption — substantial impairment.
  • Engine knock or tapping — substantial impairment.
  • Loss of power / power reduction — often safety defect.
  • Engine compartment fires — categorical serious safety defect.
  • Coolant leaks — substantial impairment.
  • Timing-chain failures — substantial impairment; risk of catastrophic engine damage.
  • Catalytic converter failure (premature) — substantial impairment.

TSB / recall overlay

Many engine defects have manufacturer TSBs or open recalls. Documented manufacturer awareness strengthens both the Lemon Law claim and the WCPA willfulness showing. Check NHTSA’s TSB / recall database for your VIN before filing.

Pacific Northwest factors

Washington’s wet, cool climate and frequent stop-and-go Puget Sound traffic contribute to:

  • Premature DPF (diesel particulate filter) clogging on turbo-diesel models.
  • Cold-start emissions issues (catalyst over-temperature codes).
  • Coolant-system corrosion accelerated by hard-water deposits.
  • Frequent thermal cycling stress on head gaskets.

Document weather and driving conditions when symptoms manifest.

Serious safety defect threshold

Under RCW 19.118.041(1)(b), an engine defect that is life-threatening or impedes the consumer’s ability to control or operate the vehicle qualifies as a serious safety defect — triggering the two-attempt threshold rather than four.

Examples almost certain to qualify as serious safety defects:

  • Stalling at highway speeds.
  • Unintended deceleration / sudden power loss.
  • Engine compartment fires.
  • Throttle hang / unintended acceleration.

What strengthens an engine-defect claim

  • Consistent symptom across multiple visits.
  • Manufacturer TSB acknowledgment.
  • Recall overlap (even if recall doesn’t apply to your VIN, pattern evidence helps).
  • Customer-relations case number open with manufacturer.
  • Independent expert inspection confirming defect.
  • Service-manager escalation documented.

What weakens an engine-defect claim

  • “No problem found” with no follow-up technician notes.
  • Driver-induced damage (overheating from low coolant, etc.).
  • Modifications that void warranty coverage.
  • Independent-mechanic repair attempts (don’t count toward Lemon Law threshold).
  • Long gaps between visits without persistent symptom.

Bottom line

Engine defects are well-covered by the Washington Lemon Law. Document each visit, secure TSB / recall pattern evidence, and (for safety defects) push to meet the two-attempt threshold. AG arbitration or court action typically follows after meeting thresholds and providing written notice.

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