Engine Defects Under Wisconsin Lemon Law

Engine defects are among the most common bases for Wisconsin Lemon Law claims under the § 218.0171(1)(f) substantial-impairment test. Wisconsin’s cold climate accelerates certain engine failures.

Common qualifying engine defects

Stalling — substantial impairment.
Misfires — substantial impairment.
Excessive oil consumption — substantial impairment.
Engine knock or tapping — substantial impairment.
Loss of power / power reduction — substantial impairment.
Engine compartment fires.
Coolant leaks.
Timing-chain failures.
Catalytic converter failure (premature).
Cold-start failures — particularly relevant in Wisconsin winter.

Cold-weather factors

Wisconsin’s sub-zero winters stress engines:

Cold-start systems — battery, starter, ignition stress.
Block heater failures.
Cold-weather fuel system issues.
Oil viscosity issues at extreme cold.

Document weather conditions for cold-related defects.

TSB / recall overlay

Many engine defects have manufacturer TSBs or open recalls.

How thresholds apply

Same § 218.0171(1)(h) thresholds:

4 repair attempts on same nonconformity, OR
30 calendar days cumulative OOS.

Within the 1-year Rights Period — then the 30-day clock + automatic doubling mechanism.

What strengthens an engine-defect claim

Consistent symptom across multiple visits.
Manufacturer TSB acknowledgment.
Recall overlap.
Customer-relations case number open.
Independent expert inspection confirming defect.
Cold-weather correlation documented.

What weakens an engine-defect claim

“No problem found” with no follow-up.
Driver-induced damage.
Modifications voiding warranty.
Independent-mechanic repair attempts.

Bottom line

Engine defects are well-covered. Document each visit, secure TSB / recall pattern evidence. The 30-day clock + automatic doubling mechanism applies once thresholds are met.

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