Shops quote $5,000–$7,000 for this one, and the quote usually isn't the ripoff, the job really is that big. Here's what's actually failing, what the correct repair involves, and the honest part: this is not a job I do in a driveway.
The Theta II 2.4 in the Sonata and Santa Fe Sport has a factory defect, not a maintenance problem: machining debris left in the crankshaft oil passages during manufacturing restricts oil flow to the connecting rod bearings. Starved of oil, the bearings wear their soft overlay away, the clearance opens up, and the rod starts hammering the crank journal, that's the knock you hear under acceleration, when cylinder pressure loads the bearing hardest.
Once a rod bearing starts knocking, the countdown is short and the failure is total. The bearing material breaks up and circulates as metal in the oil, visible as glitter on the dipstick or in the filter. The end state is a spun bearing or a seized engine, sometimes with a rod exiting the block. This defect is why Hyundai faced a class-action settlement, extended warranties on qualifying VINs, and rolled out the knock-detection software (KSDS) that puts cars into reduced-power mode when it hears bearing knock.
Here's the part most shops skip: because of the settlement, a knocking Theta II might be Hyundai's bill, not yours. Coverage depends on the VIN, the documented symptoms and the car's history, and it's worth checking properly before anyone charges you for an engine. We do that check first, every time.
If your Hyundai is doing any of these, this is the likely cause:
Not certain that's what you're dealing with? Match the symptom in plain English first:
Or describe it to the AI mechanic, it'll tell you the likely cause for your exact Hyundai in seconds, free.
See how that range compares across Mississauga, Oakville, Milton, Brampton and Etobicoke in the GTA Repair Price Index, honest shop & dealer ranges for the jobs people actually get done.
Rod Bearing Failure. Short Block Replacement (Warranty Check First) is on my published list of jobs I turn down. It needs a hoist, a press or a machine shop, and I work out of driveways with hand tools. That list is public on my trust page. I'd rather lose the job than learn it on your engine, and you should be suspicious of anyone who says yes to this over the phone.
So here's what I can genuinely do for you, holding a $5,000–$7,000 quote. Both are real, both are flat-priced, and both are worth more than a bad yes.
Before you spend $5,000–$7,000, have someone independent confirm that's actually what's wrong. This is a diagnosis, not the repair, no hoist, no lift, nothing comes apart. I scan it, test it, look at it with you, and tell you straight whether their diagnosis holds up. If it does, I say so and you go pay them with confidence.
Book the second opinion →At $5,000–$7,000 on a car that might be worth not much more, plenty of people replace instead of repair, that's a completely reasonable call. If that's where you're heading, get the next car measured before you hand over money: 150 published points, at the seller's location, written report the same day.
Book a pre-purchase inspection →Tell me what you've been quoted and what the car is doing. $100–$250 flat, at your location, and you get a straight answer either way.
Rather just have the quote read? The free quote check tells you whether the number is in line, no visit needed.
Jobs on this car that ARE mine:
Not so you can do it yourself, so you can tell whether the shop quoting you understands the job:
That's the job. It's why this one belongs on a hoist instead of in a driveway, and it's why $5,000–$7,000 usually isn't a ripoff, it's a big repair honestly priced. What's worth checking is whether that's really what your car needs.
Get the diagnosis confirmed firstPlain version: Rod Bearing Failure. Short Block Replacement (Warranty Check First) needs equipment a driveway doesn't have, a hoist to get under it properly, a press or a machine shop for the parts that come out, and a controlled space for an engine or gearbox that's in pieces for days. I work out of driveways with hand tools. That's not false modesty, it's the published limit of what I take on, and it's listed on my trust page alongside the warranty.
What that means for you: this page is here to tell you what's failing and what it should cost, so you walk into a shop knowing the job instead of nodding at a number. And if you want that number checked before you pay it, that part I can do, $100–$250 flat, at your location.
A knocking rod bearing is days-to-weeks from total failure, not months. Driving on it grinds bearing metal through the entire oil system and risks the rod letting go through the block, which can take the car from repairable to scrap. If your Theta II is knocking: stop driving it, get the warranty check done, and decide from real information. The knock never gets quieter.
Yes, with the right preparation. We need a level paved surface and space to work an engine crane beside the car, and the job spans two days. Everything else, the block, fluids, tooling, arrives with us. It's a major job, but nothing about it requires a building.
Coverage ties to the VIN, the documented failure and the car's history, the class-action settlement extended rod-bearing coverage on qualifying vehicles well past the original warranty. We run that check as step one and tell you honestly what we find. If Hyundai should be paying for your engine, you'll hear it from us before you spend a dollar.
Possibly, and we confirm before quoting: rod knock has a distinct character under load, and an oil filter inspection for metal settles it quickly. If your noise turns out to be a pulley or shield, you'll get that diagnosis and a much smaller repair, not an engine you didn't need.
No. Rod Bearing Failure. Short Block Replacement (Warranty Check First) is on my published list of jobs I turn down, it needs a hoist, a press or a machine shop, and I work out of driveways with hand tools. I'd rather lose the job than learn it on your engine.
Two things, and both are real. A second-opinion diagnostic at your car, $100–$250 flat, at your location, so somebody independent confirms that's actually what's wrong before you commit to a $5,000–$7,000 repair. And if you're weighing replacing the car instead of fixing it, a pre-purchase inspection on the replacement, $149–$399 flat, at the seller's location.
Because the useful part isn't the wrench. It's knowing what's actually failing, what the correct repair involves, and that shops quote $5,000–$7,000 for it, so you walk in knowing the job instead of nodding at a number. If you want that number checked before you pay it, that part I can do.
Send it over for a free second opinion. I'll tell you straight what the job actually involves, and if their quote is fair, I'll tell you that too.
Get a Free Second OpinionOther makes:
I'm not the guy who does this repair. I'm the guy who tells you whether you actually need it, before you spend $5,000–$7,000. Second opinion at your car, $100–$250 flat, in Mississauga, Oakville, Milton, Brampton and Etobicoke.
Book a Second Opinion Inspect a Replacement CarYour options on this one