Are Theta II engines really as bad as their reputation?

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123
Location
Minnesota
Thread starter
I have heard that Kia has a lot of nice things going for them but the Theta II engines are not one of them. Are these engines really awful?
 
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1,555
Location
Americus, GA
We had a 2013 KIA Optima. It was trouble free for 60,000 miles. We traded for a 2019 VW Tiguan. I wouldn't hesitate buying another Theta II equipped vehicle.
 
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2,354
Location
pa
earlier ones "seem" to have the issues! girlfriends 18 optima 2.4 is way better than her oil consuming 13 2.5 malibu bought new!! so far so good but time will tell + those buying new have the longest warranty of any vehicle!
 
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118
Location
MN
My 2012 Forte (Korean build, no DI) is doing fine so far. No signs of issues at 50k. That said, I see them on Craiglist with rod knocks or dead engines around 100k with some regularity. Whether that's because of faulty design or faulty owners? ¯\_(ツ)_/¯
 
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772
Location
E. Tennessee
Yes, there was some issues with certain year models 2.0T and 2.4 NA engines but they seemed to have resolved them. My engine was replaced at 76K miles with a new long-block under warranty (totally free, including the rental) and the dealer even moved over my performance modifications to the new engine. It had developed the "rod knock of death". I now have a "forever warranty" on the engine from Kia with unlimited miles and unlimited time and it even extends to all future owners (assuming I'd sell mine which I won't). I've been a very happy camper and Kia treated me right. I would have no issues buying a Kia in the future if I was in the market. As an aside: I've always used 0W-40 full synthetic oil and change it and the filter every 4-5K miles.
 
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30
Location
WestCoast
I have an 015 Optima 2.4L. I stay on top of the oci and filter changes with no complaints. I'm near 16,000miles now bought new. I like it enough to be curious of the 020' models that have the Theta III 2.5L engines.
 
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202
Location
MI
Bro had an 07 Rondo w/2.4 - never any engine mechanical problems from 70k to 170k and didn't drink a drop and would be lucky if it saw more than a dozen Oil changes during that time.
 
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3,277
Location
St. Charles County, Missouri
Debris in American engines and update kits that weren't correctly installed by dealers gave 'em a bad rep. Flaming cars can be spectacular but that was a miniscule percentage and in the past. My Nu, my daughter's gamma and my girlfriend's Lambda II are all Hertz rentals and are all trouble free.
 
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36
Location
IA
We have a 2011 Sonata as well, 72000 miles or so, and no problems so far. Turns the oil to mud after about 4000 miles, but runs like a champ.
 
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433
Location
ogdensburg new york
I had a 2010 and gave it to my son 120000 miles sofar noproblems.i have a 2015 sonata had a 2015 santafe traded for a 2020 santafe all with the 2.4 no trouble with any.change oil every 5000 miles synpower or mobile 1 great vechiles.
 
Messages
2,914
Location
GA.
*No "forever warrantee" with Hyundai Theta II engines (parent company of Kia - what's up with Hyundai and no "forever warrantee" on replacement engines ?) ... Hyundai only gives an extra 20K miles on Thetta II replacement engines . OK - that said , my 2017 Sonata 2.4 GDI Theta II burns about 1/2 to 2/3rds of a quart over a 4K to 5K mile OCI ... While you can't over come a bad design (rod bearings are now THE issue causing rod knocking / engine failure along with contributing factors of not keeping oil level to full with shorter OCI's of < 5K Mile OCI's) ... Moving up to 5W30 oil weight is thought to help provide greater film strength to rod bearings (especially in the summer hot months) . Theta II Engine Rules To Live By : * Keep oil level full at all times !! * Keep OCI's less than 5,000 miles * Move up to 5W30 oil weight D1 / Gen 2 rated synthetic oils for greater rod bearing film strength , less shearing , timing chain protection and other benefits a D1 / Gen 2 synthetic engine oil provides for GDI engines * Use only Top Tier gas * Use CRC Intake Valve Cleaner through the intake manifold every 12K miles P.S. *I am running an experimental QSUD 5W20 4K mile OCI which will go to Blackstone as a worst case baseline for my Sonata 2.4L GDI - afterwards it's back to only using 5W30 D1/Gen 2 synthetic oils !!
 
Messages
360
Location
So. Calif.
The majority of Kia/Hyundai engine failures (rod bearings, in particular) were concentrated in model years 2011-2014. In 2015, the oil pump/balance shaft assembly was redesigned and the situation has improved. The use of thicker synthetic oils and more frequent OCIs seem to help, but that's true for all GDI/TGDI engines.
 
Messages
12,454
Location
Kendall, FL
I've used both, Xw20 and Xw30 in the three 2.4L owned, much more Xw20 though. One Sonata was traded in with 188K miles. It ran 90% Xw20 without noticable burning. OCI were/are between 3000 and 5000 miles. Fuel is mostly TT. These engines have had 5w20 on the oil cap since introduced. If there were an inherent problem, the viscosity recommendation would have omitted this viscosity some time ago. The 2.0T has 190K+ miles. It gets 5w30 of various brands and recently the occasional M1HM 10w30 with 3000K mile OCI (strict). Fuel is mostly TT.
 
Messages
9,796
Location
Jupiter, Florida
In the general discussion section of another forum, (a firearms forum and not a car forum) there is a Kia tech that is quite active in such threads. I enjoy reading his very honest posts. He discusses the warranty issues at length. From reading his threads, there seems to be a continuing series of problems even with newer vehicles. All covered for newer vehicles. The fact is, the problems are not limited to US built engines and not caused by debris, despite the numerous articles claiming such. Poor maintenance is absolutely a factor, as are the inherent design weaknesses. It's good to know that poor maintenance choices will shorten engine life with other brands too. My suggestion is to choose a robust synthetic oil of higher viscosity and change it every 5000 miles. The fact is, these engine failures are closely related to a lack of viscosity, both due to thin oil choices and fuel dilution, coupled with particulate contamination. We would like to think that manufacturers produce a robust product, capable of operating endlessly with the cheapest maintenance products possible (dealership fill for example) but that's simply not the case. The reasons are self evident for those willing to look, and include inexpensive components manufactured in exactly the same manner they have been for the last 50 years, yet with lower tension rings, smaller bearings, higher cylinder pressures and RPM, long timing chains that operate position critical variable cam timing devices, contaminate producing direct injection and the move to water thin oils. Do you really expect a different result?
 
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Messages
157
Location
Texas
I have one of these 2.4 gdi engines. I can't speak to long term reliability since mine only has 15k miles but Hyundai/Kia just reached a settlement agreement earlier this month. Both companies are offering lifetime repairs free of charge for short block replacement due to rod bearing failure. With the newly developed knock sensor detection system, if your car throws a code for engine bearing failure it's covered for life.
 
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