Valvoline XL-III 5W-30 - in 2.4L Hyundai Theta II GDI Engine - Should I use it?

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I like the thicker oil and shorter oci due to soot, fuel dilution, etc. but I don't think a little thicker oil can prevent the bearing failure. It's an engine issue that Hyundai is covering with unlimited mileage and it's nice of them but I doubt if oil can resolve the issues before the fix! even if you use 40 grade and oci of 3000 miles, it could be just matter of time.
I've read reports of engines running fine using 5W-20 with over 100K miles and some failing at 40K, 60K and 80K miles with all sorts of different OCI and viscosity grades.

Maybe Hyundai got wiser and decided to ditch the 20 grade CAFE oil. Having said that, Toyota recommends 0W-20 for my Tundra with 10K oci ... so the 20 can't be that bad after all. Granted it's a MPFI and not GDI and easier on oil.
 
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ZeeOSix

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Having actual 0C numbers would give us a bit more info on base stock VI and estimated VII levels.
VI is based on and calculated with rhe KV40 and KV100 viscosities. Think they use KV40 because of the reasons discussed in post #16 by @OVERKILL ... Ie, for a more stable and accurate VI calculation.
 
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So what was the idea behind using 6 quarts of oil instead of 5.1? Because of fuel dilution?

I would say that's a risky move without extensive research!
i.e. I'm not going to listen to some tech or a service guy that supposedly thinks 0W-20 is thicker than 0W-40.
 

Rod Knock

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I would say that's a risky move without extensive research!
i.e. I'm not going to listen to some tech or a service guy that supposedly thinks 0W-20 is thicker than 0W-40.
I no longer have the vehicle. I traded it for a 2022 Jeep Grand Cherokee WK (Quadra Trac II, blacked out, etc.). The deal was very reasonable.

The tech in question was inside many of these Theta II engines. He was either rebuilding them or replacing them during the recall, depending on availability. He was their top tech, and his workload was huge compared to his compensation. When the dealership didn't want to compensate him adequately, he decided to leave. We remained friends and stayed in touch. He wasn't just some random tech but a lifelong mechanic who enjoyed his work as much as he did his grandchildren. And he knew his stuff about lubricants.

At the same dealership, I encountered the occasional tech who was briefly there until he realized that it was not a good fit or that he was incompetent and who also didn't know the difference between 0W-20 and 0W-40. These guys used an air impact gun as a torque wrench and tightened everything by the feel of their trigger finger—also, the same guys who used power tools for delicate Philips screws. Also, the same guys broke more than they fixed. Also, the same guys who I would never let work on our vehicles.

At that same dealership, one decent mechanic is left who's fixing to retire. He's their top guy, who I've known for over 15 years. I've seen him put up with weird things, including bringing costly tools from home, such as a powertrain removal table.

I didn't get my advice from "noobs" regarding the Theta II engine. I got it from knowledgeable mechanics. And by the way, none of these guys wanted to be called "techs." They always said they were mechanics—old school, kind people I can proudly call friends.
 
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"Per a friend of mine who is a Hyundai Certified Tech, he also recommended that I use 6 quarts of oil instead of the 5.1 quarts listed in the owner's manual."

I should not have used the word "some" but no disrespect. I have got a lot of bad advice from lovely friends and I still love them. I also give a lot of bad or it worked for me kind of bad advice ... It's just the nature of the game.
I also get work related bad advice from PhDs at work. Sometimes people are real expert in one particular area but that's when you have to be very careful and best is to verify!

one might think that additional 0.9 quart is insignificant ... not harmful (foaming, etc.) or helpful but who knows. I would defer to Hyundai in this case.

You would think if 0.9 quart would have solved the Theta II engine issues plus saving millions of dollars and credibility, we would have heard from them. maybe there is a TSB or some other forms of communication from Hyundai regarding this. idk

I think your were focusing too much on oil. Oil can not ultimately resolve design, manufacturing or quality related issues.

Good luck with the new Jeep. Used to own a Grand Cherokee and it was great on snow! It hardly ever fishtaled.
 
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Off topic: The OP states (like many others I've seen on these forums) that Hyundai (in particular) is a PITA with regard to warranty claims. I can only speak for myself. I'm on my third Hyundai. I've had a few minor issues and one major issue (transmission) across the three vehicles--I didn't have to provide anything in the way of maintenance records to the dealer to obtain any warranty repairs. . . and I do my own preventive maintenance, including oil changes. I've never been asked about oil changes or anything else for that matter. My dealer may be the exception, but they've been very above average to work with. They DO overcharge on many preventive maintenance services that they offer, but a polite "no thank you" always ends the discussion. When I had the transmission problem, the transmission was replaced within a week of when I reported the problem--literally with no questions asked. I can't imagine better service than this.
 
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"Per a friend of mine who is a Hyundai Certified Tech, he also recommended that I use 6 quarts of oil instead of the 5.1 quarts listed in the owner's manual."

I should not have used the word "some" but no disrespect. I have got a lot of bad advice from lovely friends and I still love them. I also give a lot of bad or it worked for me kind of bad advice ... It's just the nature of the game.
I also get work related bad advice from PhDs at work. Sometimes people are real expert in one particular area but that's when you have to be very careful and best is to verify!

one might think that additional 0.9 quart is insignificant ... not harmful (foaming, etc.) or helpful but who knows. I would defer to Hyundai in this case.

You would think if 0.9 quart would have solved the Theta II engine issues plus saving millions of dollars and credibility, we would have heard from them. maybe there is a TSB or some other forms of communication from Hyundai regarding this. idk

I think your were focusing too much on oil. Oil can not ultimately resolve design, manufacturing or quality related issues.

Good luck with the new Jeep. Used to own a Grand Cherokee and it was great on snow! It hardly ever fishtaled.
That's exactly what hyundai did. Earlier in the whole theta2 fiasco they had owners come in , hook up to a computer that listened to the knock sensor, if you fell to the left side of the bell curve on noise you got an orange dipstick instead of a yellow dip stick and it read one half qt more oil to the full mark. Later they had you come in for a neutered fuel rich tune to allow for 87 octane and less lspi. The whole thing is ridiculous. And the owners manual said 5w-30 but has an asterisk that says for added performance use 5w-40. I have a stage 2 93 octane tune and it hasn't blown up. I run 2 steps cooler sparkplugs and 2 catch cans. 2011 2.0t sonata.
 
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Off topic: The OP states (like many others I've seen on these forums) that Hyundai (in particular) is a PITA with regard to warranty claims. I can only speak for myself. I'm on my third Hyundai. I've had a few minor issues and one major issue (transmission) across the three vehicles--I didn't have to provide anything in the way of maintenance records to the dealer to obtain any warranty repairs. . . and I do my own preventive maintenance, including oil changes. I've never been asked about oil changes or anything else for that matter. My dealer may be the exception, but they've been very above average to work with. They DO overcharge on many preventive maintenance services that they offer, but a polite "no thank you" always ends the discussion. When I had the transmission problem, the transmission was replaced within a week of when I reported the problem--literally with no questions asked. I can't imagine better service than this.
This is similar to the experience I had. I have 2 Sonatas that fall under the engine warranty, a 2011 and a 2018. The 2011's engine laid down back in September; daughter was going through a roundabout and it just died. Had never gone further than 5K miles on an oil change, and had always had full syn 5w20 or more recently 5w30. To be clear, I've been a tech for more than 20 years; the only reason this car's been to the dealer since we bought it new was for warranty work or recalls; we're definitely not their best customers. They took the car in, and although unfortunately it took them a week to get it in the shop and get the diagnosis taken care of, as soon as they knew the engine was toast everything was approved, including a loaner car, no questions asked. Wasn't asked about maintenance or oil changes once. Took them 4 months to get the actual work done, but between part and schedule availability it makes sense. Plus my car appeared to be one of about 50 they had sitting on the back lot waiting on an engine. Makes me wonder if the customers having problems getting approved were at dealers that were either high volume and under increased scrutiny from Hyundai, or just run by jerks. Either way my experience was pretty painless.
 

Rod Knock

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This is similar to the experience I had. I have 2 Sonatas that fall under the engine warranty, a 2011 and a 2018. The 2011's engine laid down back in September; daughter was going through a roundabout and it just died. Had never gone further than 5K miles on an oil change, and had always had full syn 5w20 or more recently 5w30. To be clear, I've been a tech for more than 20 years; the only reason this car's been to the dealer since we bought it new was for warranty work or recalls; we're definitely not their best customers. They took the car in, and although unfortunately it took them a week to get it in the shop and get the diagnosis taken care of, as soon as they knew the engine was toast everything was approved, including a loaner car, no questions asked. Wasn't asked about maintenance or oil changes once. Took them 4 months to get the actual work done, but between part and schedule availability it makes sense. Plus my car appeared to be one of about 50 they had sitting on the back lot waiting on an engine. Makes me wonder if the customers having problems getting approved were at dealers that were either high volume and under increased scrutiny from Hyundai, or just run by jerks. Either way my experience was pretty painless.
Fuel dilution is a major problem with Hyundai GDI engines, not just with the Theta II. The problem is that Theta II engines fail in the worse possible way. The 3.3L Lambda II engine is also a major fuel diluter, probably worse than the Theta II. Premium gas is very expensive, and there is no guarantee that using it will avoid fuel dilution issues.

Hyundai's answer to the problem is to slowly implement dual fuel injection, however, that can't seem to get it right. Another software update came out for our Sonata with the 2.5L Theta III engine. This one has MPI+GDI and switches between them according to engine load and driving style. I have a feeling they "optimized" it for fuel economy and compromised reliability - just my gut feeling. I don't know, but maybe GDI doesn't belong on budget vehicles - not that you can call them that any longer at the current prices.
 
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Fuel dilution is a major problem with Hyundai GDI engines, not just with the Theta II. The problem is that Theta II engines fail in the worse possible way. The 3.3L Lambda II engine is also a major fuel diluter, probably worse than the Theta II. Premium gas is very expensive, and there is no guarantee that using it will avoid fuel dilution issues.

Hyundai's answer to the problem is to slowly implement dual fuel injection, however, that can't seem to get it right. Another software update came out for our Sonata with the 2.5L Theta III engine. This one has MPI+GDI and switches between them according to engine load and driving style. I have a feeling they "optimized" it for fuel economy and compromised reliability - just my gut feeling. I don't know, but maybe GDI doesn't belong on budget vehicles - not that you can call them that any longer at the current prices.
Strangely enough Toyota seems to have it figured out; our Sienna has the 3.5 with dual injection, and it's not hard on oil at all. Obviously Hyundai/Kia are a far cry from Toyota.
 
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Fuel dilution is a major problem with Hyundai GDI engines, not just with the Theta II. The problem is that Theta II engines fail in the worse possible way. The 3.3L Lambda II engine is also a major fuel diluter, probably worse than the Theta II. Premium gas is very expensive, and there is no guarantee that using it will avoid fuel dilution issues.

Hyundai's answer to the problem is to slowly implement dual fuel injection, however, that can't seem to get it right. Another software update came out for our Sonata with the 2.5L Theta III engine. This one has MPI+GDI and switches between them according to engine load and driving style. I have a feeling they "optimized" it for fuel economy and compromised reliability - just my gut feeling. I don't know, but maybe GDI doesn't belong on budget vehicles - not that you can call them that any longer at the current prices.
I currently maintain 2 Hyundai Theta II engines and have done two oil analysis' on each over the years-- mine show no appreciable fuel dilution with 4000 mile OCIs (well under Blackstone's limits for fuel). My wife does a lot of local stop / go driving and not a lot of long highway trips. . . . Some Hyundai engines have problems, but that hasn't been my experience. Just sayin'.
 
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Our recently traded-in 2013 Santa Fe Sport 2.0T had 261k trouble free miles using everything from VWB to ESP 5W30, but the vast majority was ILSAC 5W30 at 3k-4k miles.

The next higher mile H/K product we owned was a Sonata 2.4 which reached 118k miles before it was traded in without a single issue. 5w20 and 5w30 ILSAC 90% Of othe time at 3-5k.

We've owned 4 others in the past but their mileage was very low (>60k) before trade or sale.

I see no issue with your plan but I wouldn't put 6qts in a drain and fill 5.1 owners manual recommended fill. The thicker oils should work just fine.
 
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Our recently traded-in 2013 Santa Fe Sport 2.0T had 261k trouble free miles using everything from VWB to ESP 5W30, but the vast majority was ILSAC 5W30 at 3k-4k miles.

The next higher mile H/K product we owned was a Sonata 2.4 which reached 118k miles before it was traded in without a single issue. 5w20 and 5w30 ILSAC 90% Of othe time at 3-5k.

We've owned 4 others in the past but their mileage was very low (>60k) before trade or sale.

I see no issue with your plan but I wouldn't put 6qts in a drain and fill 5.1 owners manual recommended fill. The thicker oils should work just fine.
*I should have you buy my next Hyundai / Kia vehicle wemay !!
 
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