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

2019 Tucson 2.0L Nu Oil-Fuel Dilution (And Strange Red Color?) [ONGOING]

9K views 38 replies 11 participants last post by  13Molavi 
#1 · (Edited)
I purchased my Tucson SE in January 2020 (build date 01-04-2019). The first time I checked the oil after purchasing the vehicle I noticed the level was higher than the Full mark by about 1/2 inch (I could be wrong, but I know for sure it was over by a decent amount), but at the time I thought maybe it was filled too high, so I thought nothing of it.
In November that year, I changed the oil myself with Quaker State full synthetic 5W-30, which is what Hyundai dealers use. I changed it at 20K miles. No metal shavings were present. I made sure I filled it exactly to the Full mark. 1K miles later, the level is creeping up.

Every month I check the oil and this is what it looks like this morning:
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To compare, I checked the oil levels on a 2014 Chevy Equinox 2.4L at 73K miles and a 2018 Ford F-150 3.5L EcoBoost V6 with 27K miles (which the Ford's was changed less than 2 weeks ago). Neither the Equinox nor the F-150 displayed oil levels above the full mark. Mine also smells like gas, but so does the Equinox.
Circled in GREEN is my Tucson, ORANGE is the Equinox, and BLUE is the F-150.

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This is another view:

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It may be a little hard to tell but the Tucson is a light red-brown, the Equinox is dark gold, and the F-150 is light gold. All vehicles have been sitting for at least 12 hours and the engine is cold. About one month ago my car's oil color was more gold in color, but now it has an odd red-ish tint. When I bought the car, the color was also red-ish.

This past month I've tried to drive my car for longer periods of time because usually, I make only short trips. Last month I also tried a tank of non-ethanol 88 octane at Maverik to see if that would help, but the level looks to be the same (but I did get a little increase in fuel economy, nearly 30 in mixed driving after calculating by hand). Mechanically I've had zero issues with the engine; it sounds and drives normally.

First, has anyone noticed this with their Tucson (or 2.0L GDI Nu)? I know early versions of the Nu had some issues, but I don't recall oil-fuel dilution being one of them (or having this occur to such a new engine).
Second, is there anything else I could or should be doing to mitigate the dilution? I've changed my driving habits a lot and have done a ton of research into this but I'm always looking for other things to try.

In the meantime, I'll watch this closely and I plan to do changes every 5K miles instead of Hyundai's 7,500-mile intervals.

Thoughts?
 

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#2 · (Edited)
I find the backside (non-textured) of the dipstick better for reading a precise level.
I see the oil level rise about 1/4" in a few hundred miles, then stabilize.
The motor oil smells, but not like raw gas to me.
Your first photo looks like about 1/8" over full.

I also change oil every 5000 miles or 1 year.
However, with COVID my last change was after 3500 miles and 14 months.
 
#4 · (Edited)
What about the color? Is it normal for the oil in these engines to turn to a reddish-brown? I've never seen engine oil this color before. It almost looks like the color of transmission fluid. It shouldn't be coolant because the color is green, not red. Gold + green = a green hue.
 
#3 ·
The first time I checked the oil after purchasing the vehicle I noticed the level was higher than the Full mark by about 1/2 inch (I could be wrong, but I know for sure it was over by a decent amount)
I find mechanics often over-fill the oil (and tires!) because most customers never check these things.
Better to be a little over than let it get too low between changes.
 
#7 ·
The dipstick in my 2016 Elantra Nu 2.0 is yellow where as yours is orange. I think I read on this forum, orange dipsticks are used in engines being monitored for oil consumption and red is for replacement [warranty repair] engines. Different lengths?
The oil level in my Nu 2.0 varies more than I would like but it runs fine. Very noisey when cold. A long drive once every few weeks is a good thing.
 
#8 ·
The dipstick in my 2016 Elantra Nu 2.0 is yellow where as yours is orange. I think I read on this forum, orange dipsticks are used in engines being monitored for oil consumption and red is for replacement [warranty repair] engines. Different lengths?
I've never heard of a manufacturer doing that before. Of the issues Nu's are known for I don't recall oil consumption being one of them. The 2.4L Theta II is a lot more well known for that but I don't know what color the dipstick is. Considering how much more powerful a GDI fuel injector is compared to a MPFI one I'm not surprised some gas is getting past the rings, in addition to a very high compression ratio of 11.5:1 for my Tucson. But I don't appear to have any oil consumption.
 
#12 ·
Dipstick handle on owned Tucson is yellow (part 26611-2B610). I noticed the end used for reading oil level was discolored. Vehicle has low milage and thought that was odd that dipstick would have become discolored (have never had this occur with other vehicles). It made oil reading sometimes difficult. Thinking this may have been a defect, purchased a new OEM dipstick. It appears that the color difference is how the dipstick is manufactured and not a defect (see photo showing new item Azure Textile Sleeve Collar Denim
Outerwear Blue Azure Sleeve Line
on the right, current dipstick on left). May be difficult to see the difference in color beginning above the F downwards to tip.
 
#14 ·
Some oils come out reddish. SOPUS oils especially.
I prefer the red tint. My engines don't consume oil, having the red tint.
What's most important is when you're changing that oil. More often is longetivity-recommended (3-4k GDI / TGDI gas engine)
 
#17 · (Edited)
That UOA reminds me of a Dexos 2 oil (wth additional Moly supplement included at the factory. That's an unusual add-pack. I suspect it's a 0w20 Euro oil. Maybe even a Quaker State label, originating from the European Shell Helix lineup.

Thanks for posting that UOA and having it done Wemay. My 2.4 from 2019 with 18k now exhibits no fuel smell and no fuel streaks in drained oil. after a 3.5k run. Neither does our 2.0 Kia. I use a 50-50 blend of Pennzoil Ultra Platinum and the Dexos 2 Pennzoil Euro L Platinum 5w30s
 
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#20 · (Edited)
1 MONTH UPDATE
A few days ago I checked the oil and the level is about the same, slightly above what it was a month ago. I measured the amount over with a ruler and it's around 3/16 of an inch. So far I don't think running non-ethanol fuel helps with this issue except for a slight increase in fuel economy. I did some reading around (I think on Veloster forums) and owners of the 1.6L Gamma T-GDI commonly complain about fuel diluting the oil. I can't find the particular post again, but someone said this problem is attributed to the vehicle's "software" controlling the fuel. The vehicle thinks the engine will start knocking, so it adjusts the injection to run rich to prevent this to prevent low-speed preignition which is a common issue with direct-injected engines.

This person said to mitigate the excess fuel being injected, the engine RPM needs to be 3,000 or more, which forces the computer into making the car run leaner, thus less fuel is diluting the oil. Can anyone verify this? Or find the particular post?
Additionally, I think it was also on this forum someone recommends running premium fuel (91 octane) or higher to (I guess) force the software to inject less fuel because of the higher octane rating because LSPI is less likely to occur. Can anyone verify this as well? Here are pictures of the level and current mileage. Out of habit I check the oil in all cars every month, so I may (depending on how much I drive) continue to document the level by posting updates around once a month. If anyone else has suggestions as to what I can try to mitigate this I'd love to hear them.

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#21 ·
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).
 
#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?
 
#26 ·
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.
 
#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.
 
#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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#31 ·
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 . . .
 
#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.
 
#34 ·
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
 
#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
 
#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
 
#37 ·
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.
 
#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.
 
#39 ·
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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