Hyundai Won't Honor Their Warranty on Theta II Engine

I just had first hand experience with this issue. I have a 2011 Santa Fe that I bought brand new, currently has 153,000 miles. I brought it to the dealer because there was a tapping sound coming from the engine. My vehicle wasn’t included in the recall but my dealer went to bat for me and got Hyundai to replace the engine at no cost and they paid for a rental car for the 5 weeks it was at the dealer. Being way past the warranty they probably could have told me to take a hike but they didn’t. I changed the oil every 7,500 miles with synthetic oil without fail. The dealer told me that had to send photos to Hyundai, so I assume that they were looking for sludge. Anyway, all’s well that ends well for me. The Center for Auto Safety finally got their request approved for the NHTSA to begin an official investigation which could result in a recall for every vehicle with a Theta II engine.


well, lucky you!

at first, once I read to the part that car had 153K miles, I thought the end of the story will be quite sad

Understand the difference between MPI and GDI and why many are copying Toyota’s approach to handling the issue with dual fuel injection systems. Ford is building dual injection engines for future vehicles. Audi has had GDI’s for a while and suffer from this problem a lot. There is a problem with Hyundai (and most other) GDI (Gasoline Direct Injection) engines due to the inability to remix vapors with new fuel before it touches the intake valves. The PCV (positive crankcase ventilation) system mitigates blow-by vapors by recirculating them into the intake to be burnt in the fuel system as part of clean emissions. Every engine has this issue and all have a PCV system. What normally happens is fuel hitting the intake values cleans them, but in a GDI engine, only the air and PCV vapors touch the valves, which can coat them with as much as 10mm of carbon “sludge” coating the valves and passages that will eventually cause poor operation and engine killing detonation. It mimics the problem of not changing the oil on the proper interval. What happens is over time, oil is dilluted by fuel leading to greater vapor production being recirculated into the intake path as well as oil break down and viscosity reduction. This is why you change it. TBH, in modern tight tolerance motors, most modern oils these days can run 10k miles with no issues, especially if its synthetic because a lot of the impurities that make sludge are not in it or extremely low to begin with. This is a flaw in the engine design 100% that manufacturers are responsible for because they’ve jumped the gun without proper longevity testing. Hyundai also had a set of T2 motors that had not been properly cleaned with metal shavings in the case which scored the bearings - but that is a different issue. They’re using a “world engine” system for the block (and head I think) to shortcut engineering and keep costs down. Their motors aren’t horrible, but they’re nothing revolutionary in design if you compare it to the engineering of a Honda or even the new Nissan VC engines. Nearly all motors are GDI now to meet fuel economy requirements and you get better power delivery out of smaller displacement. Its the future and there are going to be a few hiccups (although expensive and infuriating) just as electronic fuel injection replaced carburetors. Consider installing a oil “catch can” to trap vapors before they reach the intake. I’ve read somewhere Hyundai will not void a warranty for this modification.

…and yes, if you have a warranty this “good” its probably really important to keep every record and follow the schedule. I am here researching if they actually honor it because its the ONLY reason I’d consider buying a Hyundai.

MPI or GDI… would I care if it gets me from point A to point B and does not break down over reasonable ownership period? :slight_smile:

In my personal view, Hyundai stepped to the slippery path and has yet to prove they can produce reliable vehicles, so until they can show 5+ years of clear record I will stick to the brands having better history track.

Even if they honor the warranty, I’m not sure I would want to deal with all the hassle of using it.

Name me a car brand that’s gone 5 years without any problems. That’s a ridiculous standard.


If someone is only interested in makes and models that have gone 5 years w/o problems, the list of possible cars to purchase would be… zero.

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Define reasonable ownership period.

I’m just adding my .02 that nobody has mentioned about the “sludge” factor that a lot of people have experienced with GDI motors. Its a big deal when you’re being mislead about complex information thats being used to blame the customer. “Sludge” is such a non-specific term and people should know how its used. It’s not unique to Hyundai. The more information people have, the less likely the stealerships can take advantage of you.

I know that average person doesn’t want or need to do the OCD-level research that I do before justifying an expensive purchase. I dont just go from A to B and driving is something I like doing. I’d argue that most people buy cars on some level of emotion, or there wouldn’t be so many fools in underwater loans at 84 month terms. Its a complex mechanical system that WILL eventually have failures. There are great sites like that can help with the decision. I am in no way an expert and everyone is entitled to like what they want for their own reasons.

Hyundai is just a bargain basement vehicle and they do cut corners in many unseen ways to target a price demographic. There is a lot of marketing to be recognized. I would be hesitant to buy a used one since there are far better choices that age well and depreciate slower. The warranty aspect is important.

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To say ALL vehicles from a manufacturer not have a problem for 5 years…NOT going to happen.

But I’ve personally owned a few cars that had ZERO problems it’s first 5 years. Since 1987 we’ve only owned 2 vehicles that had an issue it’s first 5 years.

The question is the percentage of cars in each manufacturer that don’t have issues it’s first 5 years. Based on several of these statistical studies from multiple sources - Hyundai is about in the middle of reliability. Not ONE US manufacturer is higher. But their not has high as Toyota, Honda or Lexus.

Meanwhile I and family members have had 4 Hondas with first-five-year problems. It’s no big deal. That’s what a warranty is for. I’m far more interested in how much the vehicle will cost me beyond that. Hyundai’s 100,000 mile powertrain warranty goes a long way toward assuaging doubts in that regard.

That said, you’re right. I would still put Honda/Toyota over Hyundai. Mazda too. But they also cost more up front.

I wasn’t defending Hyundai as some sort of gold standard of reliability, but the notion that any car company that’s named Hyundai and which has issues over a 5 year span should be avoided is simply absurd. If Hyundai “stepped to the slippery path” by having issues over a half-decade time span, then so did every other car company on the planet.

My current Outback has had one problem–so far–in 8 1/2 years. At about the 2 year point, the sensor for a low level in the windshield washer reservoir went bad, so they simply replaced the reservoir. That’s it, and–of course–it was covered by warranty. If that had happened after the 3 yr Bumper-to-Bumper warranty expired, I would have just ignored that insignificant warning light.


There’s evidence that intake valve deposits are not caused by PCV material, but rather by EGR.

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Sludge is an oil problem in the oil galleys and pressure system. Not the same thing as carbon buildup on the intake valves on GDI engines. ANY engine can get sludge in the oil system, GDI, dual injection or multi-point intake injection. The GDI problem engines are those with poor EGR control and poor blow-by control building fluffy carbon on the intake valves.

EGR from scavenging or overlap? I could see that making a contribution. I’d still put a catch can or at least run cleaner through the intake side periodically. I’ve heard if it blows carbon chunks through the exhaust it can clog the cat and/or beak turbo fins. I’ve seen MPI cars that had massive coatings in the intake runners due to blow by too. Still, there shouldnt be any EGR function that would put vapors into the crank case causing the need for ventilation. Its still got some kinks to work out imho. Unfortunately, all the manufacturers are producing GDI systems for these small engines. It looks like Honda has put their injectors partially in the path to hit the valve when its open, perhaps to fix this. Now if they only solve the fuel dilution.

Thanks for the link.

Well, I thought they were referring to and calling sludge and ICD the same thing. I realized that there is a difference, but I was confusing in the description. Do cars experience oil sludge in the case if you at least change the oil every 10k these days? I would have thought that those deposits are a thing of the past with synthetic oils.

Considering how many cars spec synthetic from the factory, the extended oil chane intervals and problems with sludge… I’d have to say sludge is an issue. I have never done oil changes at 10k nor do I use anything but synthetic and I have never had a sludge problem. I have cleaned up a few high mile used cars I bought with my use of synthetics, however.

That said, there seem to be a lot of sludge complaints on certain engines. Maybe the owners are not very good about maintenance and go, 15k on an oil change. Or even longer. They may drive severe schedules that require 5k or 7500 mile changes and still change at 10k. Some may use lower grade oils than recommended. The pros here may be able shed more light on this.

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I think a lot of it is maintenance too. My MR2 has the 5sfe engine, which is “known” as a sludgy motor. I had the valve cover off last year at 180,000 miles, and it’s nice and clean under there, but I also keep up with oil changes.


It always seems as though the sludgy motors are owned by someone else. I don’t know any one of my car-savvy friends that have had this problem.

I did, however, pull an old truck engine so I could use the block for my race engine. The inside of the engine looked like someone had barbecued a PIG in there! We scooped it out with garden shovels! Well seasoned block!

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Did I tell about “any problem” ?
I did not.

It would not be reasonable to apply this criteria toward windshield wiper blades, would it not?

If we go from the different direction, is it reasonable for the car under 100K miles to experience any major break-downs, not as rare occurrence, but above the “average rate” of the similar vehicle class?
In my view, it is absolutely not.
By this criteria, I think that Nissan is currently on the black list for their above-reasonable failures in CVT transmissions over decade already, Hhyunday shares this row for their seemingly never-ending engine problems, etc…
I do not claim to know the exhaustive list of these, but I tend to study the makes/models I consider purchasing to make my mind if I want to wander into these waters.

Would it be reasonable to look at the car maker marketing claims of “all new!” / “completely redesigned!” / etc… and expect that reliability will be top notch if the same make/model shows year after year of particular problem?
Maybe I exaggerated about “5 years” term, but IMHO the test of “did they show reasonable history track?” still stands.

I read other comments above and to my surprise found that I was understood as if I was asking for the particular car I would buy to show zero problems over 5 years of ownership, but it is not what I really implied and here I probably did not explain myself good enough.

I implied that if I’m buying some Make/Model combination, it shows a history of good quality over the last 5 years, so I’m not buying blind. Im’m not an early adopter making decisions on sales pitch.

I absolutely expect that car will have problems here and there and I would be ready to deal with oil changes, wiper blades and brake pads :slight_smile:

I’m absolutely against dealing with broken transmissions, blown head gaskets, seized engines and such :slight_smile:

The thing is, these days no one company makes 100% great cars or 100% crap. So just because Honda had problems with certain Civic engine castings, doesn’t mean the Accord (or even a current Civic) is a bad purchase.

And just because lots of cars got recalled in 2016 because of faulty airbag inflators (thanks, Takata!) doesn’t mean you shouldn’t buy a Honda/Acura, or a Toyota/Lexus, or an Audi, or a BMW, or a Cadillac/Chevy/GMC, or a Chrysler, or a Ferrari, or a Ford/Lincoln/Mercury, or a Mazda, or a Mercedes, or a McLaren, or a Mitsubishi, or a Nissan, or a Subaru, or a Tesla, or a Volkswagen… Because all of those cars (and that’s just a partial list) had a recall for a very bad problem with their airbags, but that doesn’t mean they all universally suck.

I hear you, and agree on that logic of “nobody is perfect”, I’m only coming from the different perspective and different definition of “what is a failure”.

When I tell “MakeX/ModelZ sucks”, it means one would have a high risk of either major inconvenience under warranty or risk of major repair shortly after warranty period.
I’m not talking about replacing brake pads or for example engine mounts I had to do in my Nissan: this is low-risk and no catastrophic break-down.
Inconvenient: YES, costly: not really, critical/catastrophic: NO.
Having engine seized or CVT broken to “no-go” state or something a local garage can not fix in a day is a definition of a major failure for me.

Let’s assume I go shopping and by exterior features I like MakeX / ModelZ so much I can not eat.
If I know from the MakeX / ModelZ historical reliability performance that they have no “major” problems in the above definitions, then it may go on my shopping list, otherwise, “no, thank you”.

On my last purchase, I started off with 9-10 Make/Model combinations I considered as potentially fitting profile. I knew I will not buy some of them, but still included into the shallow research, just to cover the basics. Third of them were immediately eliminated on the quality history trail consideration I mentioned, then another third were out on other criteria closer to “need/want” factors, then test-driving phase began.

I know that “past performance is not a guarantee of future results”, but often past bad performance is a good indicator of likely problems in the future.