Hyundai and Kia Engine Knock: The Theta II Recall, What Is Covered, and What to Do

That Knock Is a Known Problem

If your Hyundai or Kia has started knocking, ticking, or rattling from the bottom of the engine, especially at idle or under light load, you are not imagining it and you are not alone. The Theta II engine, the 2.0-liter and 2.4-liter four-cylinder in most Hyundai and Kia sedans and SUVs from roughly 2011 to 2019, has a manufacturing defect that leaves metal debris in the crankshaft oil passages. The debris starves the connecting rod bearings, the bearings wear, the rod knocks, and eventually the rod goes through the block.

Hyundai and Kia have recalled, extended warranty, and settled a class action over it. A lot of knocking Thetas are owed a free engine. The trick is knowing whether yours is one of them before you pay anyone for a diagnosis, including us.

Which Cars Have the Theta II

Hyundai	Kia	Engine
Sonata 2011 to 2019	Optima 2011 to 2019	2.4L GDI, 2.0L turbo GDI
Santa Fe and Santa Fe Sport 2013 to 2019	Sorento 2012 to 2019	2.4L GDI, 2.0L turbo GDI
Tucson 2014 to 2019 (2.4L)	Sportage 2011 to 2019	2.4L GDI, 2.0L turbo GDI
	Soul 2012 to 2019 (2.0L)	2.0L Nu GDI (separate but similar issue)

The Elantra and Forte with the 1.8L and 2.0L Nu engines have their own rod-bearing problem with a separate extended warranty. The Kona, Veloster, and anything with the newer Smartstream engines are not part of this.

Symptoms, in the Order They Show Up

• A metallic knock or rattle from low in the engine, louder at idle when warm, sometimes mistaken for an exhaust heat shield. This is the rod bearing. Once you hear it, the engine has weeks, not months.
• Oil consumption with no visible leak. Topping off a quart between changes is an early sign on these engines.
• Check engine light with a P1326 code. That is the Knock Sensor Detection System, software Hyundai and Kia installed under the recall. It listens for bearing knock and puts the engine in a reduced-power limp mode to keep the rod inside the block. P1326 is the computer telling you the engine is failing.
• Loss of power, stalling, or a sudden no-start on the highway. The late stage. If the car stalls and will not restart, do not keep cranking it.
• Engine fire in the worst cases, which is why this became a safety recall and not just a warranty problem.

What the Recall and Extended Warranty Actually Cover

There are three separate things, and dealers do not always explain the difference.

The recalls (2015 and 2017). Hyundai recalled 2011 to 2014 Sonatas, then 2013 to 2014 Santa Fe Sports and the matching Kias, for the debris problem. The dealer runs a bearing clearance test. Fail it and the engine is replaced free. Pass it and you get the knock sensor software, which is the P1326 system above.

The lifetime engine warranty. Out of the class action settlement, Hyundai and Kia extended the warranty on the Theta II short block to the lifetime of the vehicle for original and subsequent owners, covering rod bearing failure specifically. That is the one most owners do not know about, and it is the one that matters if your car is a 2015 to 2019 that was never recalled. The engine has to fail from the covered cause, and the dealer decides, but a knocking rod bearing on a Theta II is the textbook case.

The knock sensor update. If the dealer installed the KSDS software and the engine later throws P1326, the warranty replacement is supposed to be straightforward. If the software was never installed because the car never went in, the dealer will usually do both at once.

What can get a claim denied: a missing oil change history, evidence of running the engine low on oil, or an engine that was already opened by someone else. Keep every oil change receipt. If you have had the work done at our shop, we have the records.

What to Do If Yours Is Knocking

1. Stop driving it. A knocking rod does not get better and the difference between a warranty engine and a denied claim can be the rod going through the block on the highway.
2. Check your VIN at nhtsa.gov and on Hyundai's or Kia's owner site. Open recalls show there.
3. Call the dealer, not us, first. We would rather tell you that than take a diagnostic fee for an engine the manufacturer owes you. Ask specifically about the Theta II lifetime short block warranty and the bearing clearance test.
4. If the dealer denies it, or the car is out of the covered population, come see us. We confirm the diagnosis with an oil analysis and a bearing noise check so you know what you are dealing with before deciding anything.

What It Costs When It Is Not Covered

Job	Typical cost	Notes
Diagnosis	$100 to $160	Scan for P1326, listen with a stethoscope, cut the oil filter open and look for bearing material. Applied to the repair.
Remanufactured or used engine, installed	$4,500 to $7,500	The usual repair. A used engine from a newer, post-fix car is often the better value than a reman of the same design.
New long block from Hyundai or Kia, installed	$7,000 to $10,000	What the dealer installs under warranty. Rarely worth paying for out of pocket on a car this age.
Rod bearing replacement only	Not offered	The debris is in the crank. New bearings on a contaminated crank fail again. We do not do this repair and would not recommend anyone who does.

Written estimate first, 12-month / 12,000-mile warranty on the engine work. Whether the car is worth it depends on the rest of it; a 2016 Sonata with 90,000 miles and a clean body usually is, and we will tell you straight if it is not. More on how we approach a job this size on the engine repair page.

Keeping a Healthy Theta Healthy

Not every Theta II fails. The ones that last share a pattern: oil changed every 5,000 miles with the correct 5W-20 or 5W-30 full synthetic, oil level checked monthly because these engines consume some, and no extended idling. If the knock sensor update has been installed, leave it installed; it is the thing that catches a failure before it becomes a fire. We service Hyundai and Kia with the factory-level scan tool these engines need, and if a check engine light is the first sign you have seen, start with the most common check engine light causes.