I have a 2015 Hyundai Sonata, and the original Theta II engine was one of the "bad" ones. I've never heard an engine knock so badly, it went at about 122,000 miles. I had no issue at all with my local Hyundai dealer replacing the engine on warranty in September of 2022. Almost 4 years later and 50,000 miles, the new engine hasn't used the first drop of oil. Regular high quality synthetic oil changes every 3-4,000 miles. So far so good. Anyone else gone through this? And if so what's your experience been?
Anyone else had a Hyundai Theta II engine replacement?
- Thread starter Bigvman23
- Start date
Not me but the kids baby daddy had 2 engine replacements. First about 150k and the 2nd at 190.
Did he have the same issue with the 2nd one?
Ya it blew up
We have a 2012 Sonata 2.4 that received a new long block at 135k miles? I have to check my notes. Now my son’s daily at 165k. Recently thought it was consuming oil again but found a loose oil filter that was leaking profusely. (What numb nuts did the last oil change I wonder… oh right, me) So that was quite a relief 
Well better than it going out the tailpipe I guess.We have a 2012 Sonata 2.4 that received a new long block at 135k miles? I have to check my notes. Now my son’s daily at 165k. Recently thought it was consuming oil again but found a loose oil filter that was leaking profusely. (What numb nuts did the last oil change I wonder… oh right, me) So that was quite a relief
Yup. A much simpler & cheaper solution (than paying for a new cat).
Well better than it going out the tailpipe I guess.
My friend has one, the original engine was replaced ~5 or 6 years ago at 98k miles, the current engine has ~95k miles. It's currently driven by his daughter; they're not car people at all, so no idea how diligent she is with the oil changes. IMO it's a ticking time bomb.
Funny thing is, I was watching one of the many car/engine based YouTube channels that I do a few weeks ago, and the host was tearing down a Theta II engine relatively close to the same year I have. He stated he thought it was actually a decently designed engine, fairly basic, and evidently it was the execution of manufacturing it and not necessarily a bad design that was causing all the trouble (I know they are blaming it on not cleaning parts properly and having small shavings in the block). Hoping to get many more miles out of this replacement. Almost due for an oil change so I'll probably run a can of intake valve cleaner trough it this weekend and change it this week. Also going to switch from the Purolator Boss to the Purolator One. I've been running the Boss for years and I'm really disappointed at some confusing information with its micron rating. Evidently it may only catch particles around 45 microns or bigger. It sounds like that may depend on the model you get, but I'm not taking the risk. The One catches 20microns, and is actually cheaper.
I have seen 3 of these come to the shop, all 3 times I pulled the extended coverage paperwork and gave to the customers to take to the dealership - they all had their motors changed. Hyundai/Kia gave them no troubles with the engine replacements.
Not checking oil is a serious problem in society today. For every 10 cars that come in - 7 or 8 are low on oil and a often nothing in the stick!
It's always been a problem, well at least since full service gas stations quit being a thing! With longer OCIs and low tension rings it has got worse.
I bought three beaters (Saturn Ion, Pontiac Vibe, Lexus ES300) for the grandkids and told them if I catch one more than a quart down I'm doing a re-po. So far so good.
I've mentioned this before but my niece had one fail at 150,000 miles (she was the third owner of basically a beater with minimal documentation available on maintenance history) and the dealer put a used engine in for the cost of new fluids.
I was pretty impressed thinking they want customers to come back and buy a new one some day.
Not sure of the quality/history of what they installed but it's run 10.000 miles without problems.
I was pretty impressed thinking they want customers to come back and buy a new one some day.
Not sure of the quality/history of what they installed but it's run 10.000 miles without problems.
According the the I_Do_Cars (YT) guy, it's predominantly No. 3 that eventually self-destructs. 
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