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Does your 2016-Present 2.0L or 2.4L Tucson Exhibit Oil-Fuel Dilution?

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Check the oil level every 500 miles and get that fuel level tested as needed. Use mileage as an indicator - not the 30 day calendar.
Your dipstick oil level reads the same as mine. Keep that engine full of oil and use 5w30 or possibly 40, depending on if it's GDI or TGDI.

I use a blend of Pennzoil Dexos 1 and Dexos 2 in 5w30. My cst @ 100 usually ranges near 11 (virgin oil).
 

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I use a 50-50 blend of Pennzoil Ultra Platinum and the Dexos 2 Pennzoil Euro L Platinum 5w30s

Wemay, what is the reason for mixing the two oil types?
I wrote that comment.
I do it to get the viscosity number up from 10 to 11 using 5w30 and remain within the two Dexos specs. It increases HTHS, plus lowers NOACK and Ash levels.

Dexos 1 oils are more for CAFE ...MPG increases. Dexos 2 oils are tougher, thicker oils (mostly European) that are designed better (my opinion) for TGDI /GDI. Blending them together reduces the European-style viscosity thickness. I don't want my 2.4 GDI or 2.0 MPI having 12cst virgin oil here in Michigan and I want thicker than 10cst, without sacrificing GTL base oil. In other words, I am not using cheaper base oil like Supertech, which does offer a 11cst virgin oil in 5w30. I get less shearing using GTL over Warren's Supertech thicker base oils. The reason they start off at 11.6 is because their 5w30 should be called Shear City oil. The GTL shears less.

.... and no, I'm not getting into a long debate about this. Let Google Search teach interested readers of this thread more. I don't have the time for it. Bobistheoilguy can help with that search also.

I'm out of this thread. Just too much explaining and detailing this-type topic.. No thanks.
 
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White Pearl 2019 Hyundai Tucson SE FWD
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Discussion Starter · #25 · (Edited)
2 Month Update - Oil Level Is Decreasing

A few days ago I checked the oil level again and was very surprised that the level appears to be decreasing a little compared to last month. The decrease isn't a lot, but it is noticeable.
Since the last time I checked it, I've only driven 80 miles. The only thing I did differently is I put in premium fuel (91 octane) from Costco. Before I was using 88 non-ethanol which didn't appear to make any difference. Having put in premium fuel and seeing the level decrease may be a coincidence, but I'll continue to watch it. I'm slightly pleasantly surprised to see that fuel is not increasing the oil level at the rate it was before, but I hope this means I'm not burning oil :-/

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I wrote about the following in another thread (and made a video of it), but the only strange thing I noticed lately is sometimes if my car sits for several days it makes an odd knock or clattering noise. My first thought is maybe piston slap but I'm not sure. Given I only have 21K miles, I hope I'm not already experiencing something like that. I've read plenty of horror stories of Elantra Nu's experiencing these kinds of problems. Whatever I heard, it sounded odd (and it's not the noisy DI sound. This is different). It's hard to describe but it can easily be heard in the video I made. It seems to go away once the engine is warm, but I might possibly hear it at around 2,000 RPM, but can't hear it any higher or lower than that (but my ears could be wrong). Has anyone else experienced this?
 

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Great thread and excellent info on here. I use Castrol Edge 5w40 and have used 5w40 full synthetics either from Shell, Mobil or Castrol ever since dumping the first factory oil. My oil darkens reasonably quickly but I have a heavy foot and drive my 2.0 NU Tucson in 'Sports' mode 99.9% of the time as I want to avoid knock by keeping the revs elevated. I also use premium fuels (95 and 98 here in NZ) for best ignition and their cleaning agents. I don't use injector cleaner as recommended because of this. My oil changes occur every 7500km's and both my Tucsons have had this treatment from new. My oil always smells of fuel when I do the oil changes. It's just a function of GDI engines as some of the fuel sprays on the cylinder wall where it mixes with oil film and ends up in the oil. It's a gradual and slow process but as my revs are high and I have a lead foot it must speed this up. I have no consumption of oil at all and technically, hot oil should evaporate most fuel in the oil via the PCV system.
 

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Discussion Starter · #27 ·
Great thread and excellent info on here. I use Castrol Edge 5w40 and have used 5w40 full synthetics either from Shell, Mobil or Castrol ever since dumping the first factory oil. My oil darkens reasonably quickly but I have a heavy foot and drive my 2.0 NU Tucson in 'Sports' mode 99.9% of the time as I want to avoid knock by keeping the revs elevated. I also use premium fuels (95 and 98 here in NZ) for best ignition and their cleaning agents. I don't use injector cleaner as recommended because of this. My oil changes occur every 7500km's and both my Tucsons have had this treatment from new. My oil always smells of fuel when I do the oil changes. It's just a function of GDI engines as some of the fuel sprays on the cylinder wall where it mixes with oil film and ends up in the oil. It's a gradual and slow process but as my revs are high and I have a lead foot it must speed this up.
If you're using premium fuel you shouldn't have to worry as much about knocking since higher octane ratings have more knock resistance. With this in mind, I don't think it would be necessary to drive your car hard, which you say speeds up the dilution. Coincidently when I put in premium my oil level dropped a little and I don't drive my Tucson hard. Maybe premium fuel is a fix to the dilution? I guess only time will tell. I'll continue to post updates about my experience.
 

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Discussion Starter · #28 ·
I checked it a few days ago and it looks like the level it's increasing a little bit now. Since my last post I've only driven 27 miles (I've been out of town a lot and take a different vehicle). It's too early to tell if premium fuel mitigates dilution. I need to drive the car more.

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The only advise I can give you is, if you love your engine as much as you appear to be ( changing oil every 5k) then continue to not do short journeys. Worst thing for an engine that is.If anything take a long detour.
 

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Discussion Starter · #31 ·
The only advise I can give you is, if you love your engine as much as you appear to be ( changing oil every 5k) then continue to not do short journeys. Worst thing for an engine that is.If anything take a long detour.
I wish I could drive longer but every place I need to go is within 6 miles or less. And it's frustrating stop-and-go traffic where the speed limit doesn't exceed 40 mph. Rarely I'll drive on the freeway and do a loop circling town and come back but I hate the thought of wasting gas just to (possibly) mitigate this problem (where I live I've seen fuel prices as high as $3.99 so I hate the idea of deliberately wasting gas, especially if 91 premium (more expensive) will prevent dilution more than 87). I'm also planning to do oil changes every 3,000 miles instead of 5,000. Smh sometimes I wonder if I should have bought an electric car . . .
 

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I wish I could drive longer but every place I need to go is within 6 miles or less. And it's frustrating stop-and-go traffic where the speed limit doesn't exceed 40 mph. Rarely I'll drive on the freeway and do a loop circling town and come back but I hate the thought of wasting gas just to (possibly) mitigate this problem (where I live I've seen fuel prices as high as $3.99 so I hate the idea of deliberately wasting gas, especially if 91 premium (more expensive) will prevent dilution more than 87). I'm also planning to do oil changes every 3,000 miles instead of 5,000. Smh sometimes I wonder if I should have bought an electric car . . .
Sounds like you should have bought a low cost used clunker! Sorry meant no disrespect.
Short miles hardly ever driven.
 

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Discussion Starter · #33 · (Edited)
I'm late posting this but the level is basically the same as last time, maybe slightly higher but it could be the way I was holding the dipstick. Since then I've driven 30 miles. School is starting soon and I'll be driving about 10 miles a day 5 days a week. It'll all be city driving. I don't know when I'll ever be able to incorporate extended highway driving. And where I live fuel is officially more than $4 a gallon so I don't want to deliberately waste gas.
 

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You didn't mention hybrid. So....Sell the current one - then buy an electric. Only ones I see around here are the Chevy Volt/Bolt.
With higher costs of electric vehicles and battery failure to expect eventually, your savings on fuel costs should reach the break-even point in about 15 years......lol
 

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Discussion Starter · #35 · (Edited)
UPDATE

I've been very busy and haven't posted in a while but the level has remained about the same, maybe slightly less. Since the last time I posted an actual picture rather than a text-only update I've driven more than 400 miles, 90% being stop-and-go traffic. One day I also performed spirited driving for the purpose of recording acceleration clips that will be compiled into a YouTube video about this engine's performance (multiple 0-60 runs and, compared to what the engine normally experiences, longer intervals of high RPM). In this time, the level doesn't appear to have increased.

I started this thread on March 30 of this year. Comparing the March photo to this one I took today, the levels look about the same, but I've driven hundreds of more miles. I last changed the oil in November 2020 and the level began to slowly creep up and continued to creep up as I used 87 octane and 88 with no ethanol (88 for a short period of time). I'm happy to say, though, since using premium fuel beginning this June, the level has remained about the same. Since switching grades, the level hasn't necessarily decreased from what it was starting out, but it hasn't really increased. The Equinox now has 77K miles and has more dilution than mine, and the F-150 also has some dilution. Both of them continue to use 87 octane. All of our oil continues to smell like fuel, but the Equinox especially reeks. This experiment is still ongoing and will be for many more months but I'm pleased to see the level is no longer noticeably increasing. So far my hypothesis of using higher octane fuel to mitigate dilution seems to be true.

Automotive tire Hood Motor vehicle Automotive design Bumper



Automotive lighting Automotive mirror Automotive tire Rim Steering wheel
 

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Discussion Starter · #36 ·
2 UPDATES

I'm super late posting this update and I'm including last month's information as well, for check dates October 31 and November 24. The mileage for the October picture was around 22,033.
Given how much gas prices have gone up ($4+ a gallon) I'm no longer deliberately taking a slightly longer route beginning in November. And frankly I don't think driving the car for a little longer makes any difference in fuel dilution based on the pictures. The level looks about the same. So far since using premium fuel it hasn't really risen at all.
Tomorrow it'll get a lot of freeway exercise for the first time in a really long time as I leave for Thanksgiving (2 hours each way).

Taken October 31:

Fluid Kitchen sink Sink Gas Automotive wheel system



Taken November 24:

Hood Automotive lighting Automotive tire Grille Automotive design



Mileage as of November 24:
Brown Automotive lighting Automotive tire Automotive design Font
 

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I don't see how higher octane fuel can reduce dilution in a non-turbo engine, so save your money.
Other than occasional road trips I've also been driving little, and mostly city, 2700 miles in 8 months since the last oil change.
My oil level rises 1/8 to 1/4 inch after a few hundred miles and stabilizes.
My last short road trip of ~300 miles dropped the level a bit, then it comes back up.
 

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Discussion Starter · #38 ·
I don't see how higher octane fuel can reduce dilution in a non-turbo engine, so save your money.
I'm convinced using a higher octane is helping. I don't think the pictures are lying. Initially upon switching from 88 non-ethanol to 91 the level dropped significantly in just 80 miles of all-city driving. The level kept rising when using 87 and 88 non-ethanol but has gone down and stabilized since using 91. I don't think it's a coincidence. From what I know when the vehicle's ECU detects knocking, (a lot of time we can't hear it) it'll adjust the ignition timing and/or alter the amount of fuel entering the combustion chamber, which can result in excess fuel entering inside. It's then not always burned off and is sucked past the cylinder rings and mixed with the crankcase oil. A higher octane fuel has higher knock resistance, limiting or preventing the occurrence of knocking, thus mitigating this fuel dilution.

And I don't use premium fuel solely in trying to stop fuel dilution. I use it as an extra way to prevent long-term engine problems. Long-term knocking/abnormal combustion can cause cylinder and piston scoring, leading to piston slap and other major problems, which the Nu has a propensity to develop as early as 60K miles. Piston slap is very common in Elantras. Preventing this abnormal combustion is important for long-term reliability. This abnormal combustion causes a “shock” wave that travels throughout all the engine internals including the connecting rods. Knocking instantly creates a peak of cylinder pressure in addition to the remaining combustion the piston is subjected to. This subjects it to unintended forces which it's not designed to accommodate, such as side forces, causing cylinder wall scoring.

Given the intense internal pressures and high compression ratios modern engines have these days, I theorize 87 octane is no longer high enough and premium fuel such as 91 is the true requirement even though the automaker says 87 is good enough. In other words, Hyundai, and many other automakers, are recommending an octane that's too low than what the engine actually needs, and owners could be unknowingly paying the price over the long run.
 

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The Hyundai Direct injection engines are not well built IMO. We have one Theta II that is burning 1 qt every 400 miles and getting worse. Waiting for the engine to seize (great plan Hyundai!). My Veloster Turbo, seems like it is starting to use some oil despite being babied with synthetic oil every 3 K miles. It has 70K miles on it.
 
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