Used Car InformerUsed Car Informer

2011-2019 Hyundai Sonata: Theta II engine failure pattern

KNOWN MAJOR RISK
known major failure pattern on this model

What goes wrong

Federal recalls 17V226000 and 18V934000 cover engine failure on 2011-2014 Sonata and 2013-2014 Santa Fe Sport. The 2.4 GDI Theta II can spin rod bearings and seize, knocking noise, then total failure, sometimes fire. Major recalls, a knock-sensor software campaign (KSDS), and class-action extended warranties exist; coverage depends on the KSDS update having been done BEFORE failure.

Federal record for the 2015 Hyundai Sonata, pulled from NHTSA when this page was built:
1137 owner complaints on file , most-reported: ENGINE (399) · ELECTRICAL SYSTEM (142) · POWER TRAIN (125).
9 safety recalls listed.
Complaint volume tracks how many were sold as well as how they held up , read it as a pattern, not a score. Counts change; confirm live at nhtsa.gov or by running the free check below.
Rough cost: $4,000-$6,000 engine · recall coverage possible. Broad estimates , labor rates and parts vary widely by region and shop.

What to do about it

Before you hand over cash: Run the VIN through the recall check below FIRST. Dipstick on a white towel: metallic glitter = walk. No proof of the engine recall/KSDS work = treat the engine as unfunded liability.

Whatever you find, a $100-150 pre-purchase inspection by an independent mechanic is the cheapest money you’ll spend on any used car , including this one.

Run the full free check on this Sonata →

Free · no signup · federal recall + complaint data included

← All buyer's guides · Keep Your Car Alive (free DIY guide)

General reference information only , not a mechanical inspection, appraisal, or vehicle history report, and not specific to any individual car. Failure patterns describe documented tendencies across many vehicles; any single car may be better or worse. Cost figures are rough estimates , verify locally. The absence of a warning is not a statement that a car is safe or problem-free. Always verify recalls directly with NHTSA and get a pre-purchase inspection. Not affiliated with any manufacturer, dealer, or reporting service. No affiliate links, no commissions, no ads. © Used Car Informer, operated by MCC LLC · v6.6