2012 Kia Optima 2.0T Rotella Gas Truck 5w30 167000 miles fuel dilution 3000 miles on oil

[Resyek83]

I recently performed a couple UOA's on my 2012 Kia Optima 2.0T. Both intervals of around 3k miles or so. This is one of those dreaded "theta 2" engines that arent known for durability, so I havent gone much farther than that. The engine is all original, vehicle is all completely stock. I have a fuel dilution problem, I replaced the high pressure fuel pump after the first test and had even more fuel in the oil on the second test, so that pump probably wasnt bad, I guess I'll keep it as a spare. I've heard of fuel dilution on some of these GDI engines but you'll also find some out there that are just fine. My daily commute is about 7-8 miles which probably counts as short trips, there's 4 or 5 stop signs along the way 40mph top speed, but I get out on the weekends for longer trips too. Should I be switching to a 5w40 for some extra safety margin on the oil viscosity? Its thinning out to a 20w after only 3k miles, and the TBN is getting eaten up just about as fast. On the plus side, my wear metals look good.

 

[B1974]

Do you live in a cold climate? Fuel dilution gets worse as the temperature drops. I'd change 5w30 in your car at 2500k or try the 5w40 like you are and go for 3000k with that.

 

[Gimpy1]

View attachment 82592

I recently performed a couple UOA's on my 2012 Kia Optima 2.0T. Both intervals of around 3k miles or so. This is one of those dreaded "theta 2" engines that arent known for durability, so I havent gone much farther than that. The engine is all original, vehicle is all completely stock. I have a fuel dilution problem, I replaced the high pressure fuel pump after the first test and had even more fuel in the oil on the second test, so that pump probably wasnt bad, I guess I'll keep it as a spare. I've heard of fuel dilution on some of these GDI engines but you'll also find some out there that are just fine. My daily commute is about 7-8 miles which probably counts as short trips, there's 4 or 5 stop signs along the way 40mph top speed, but I get out on the weekends for longer trips too. Should I be switching to a 5w40 for some extra safety margin on the oil viscosity? Its thinning out to a 20w after only 3k miles, and the TBN is getting eaten up just about as fast. On the plus side, my wear metals look good.

You can change the oil every 100 miles and still have the engine go. Its not an oil issue causing failure. If you havent gotten it done go to your kia dealer and get the ksds update that way your engine is warrantied for life. You must have the ksds update completed or you will not get the warranty, goggle kia class action lawsuit theta 2.

 

[Junk]

Serviced my 2011 Sonata 2.4 every 3-4K with full syn 5w20 or 5w30 and didn't matter, let go at about 80K. Incidentally, that was at the beginning of September, and my car is still at the dealer waiting for repairs.

 

[JavierH19]

if it was my engine id plug an obd2 in like any elm 327 and check fuel trims. I'd also bump up to a cheaper syn blend 10w-40 since it made rgt 5w-30 go from 11.8 to 7.3 cst in just 3k. But a 14-15cst would probably be 10-11cst at the end so a 30 grade.

You have something of an injector issue, that's way too much fuel and i believe fuel % cuts off at 5 so its probably more. now if you plan on owning it for a very long time id probably get it fixed but if i were you id kick it.

 

[JavierH19]

Serviced my 2011 Sonata 2.4 every 3-4K with full syn 5w20 or 5w30 and didn't matter, let go at about 80K. Incidentally, that was at the beginning of September, and my car is still at the dealer waiting for repairs.

Now thats just baloney. What kind of dealer sits on a customers car for almost 4 months. i assume its under the 10y/100k warranty.

Isn't there a law saying that if a warranty repair takes longer than 30 days you can have it lemon lawed and get a full refund. if i were you I'd seriously consider the options. You could get a full refund on it.

 

[JoelB]

Now thats just baloney. What kind of dealer sits on a customers car for almost 4 months. i assume its under the 10y/100k warranty.

Isn't there a law saying that if a warranty repair takes longer than 30 days you can have it lemon lawed and get a full refund. if i were you I'd seriously consider the options. You could get a full refund on it.

If the engines are on backorder there's nothing the dealer can do.

 

[MParr]

The 2.0T Theta II engines of that era allowed the use of 5W40 oils. Some other things that you can do is run premium fuel, keep it out of the Eco Mode, and air it out every once and awhile.

 

[Gimpy1]

Now thats just baloney. What kind of dealer sits on a customers car for almost 4 months. i assume its under the 10y/100k warranty.

Isn't there a law saying that if a warranty repair takes longer than 30 days you can have it lemon lawed and get a full refund. if i were you I'd seriously consider the options. You could get a full refund on it.

No its not, there is a delay because of the class action lawsuit. Same thing happened with the Takata airbag recall. You are also entitle to a rental, if you can find one.

 

[Gimpy1]

The Theta 2 engine failure in NOT oil related, you can change the oil every day, use super expensive fully synthetic solve the world's problems oil and it will NOT make an ounce of difference. Read the class action lawsuit. If you have a Theta 2 engine get the KSDS update and you have a lifetime engine warranty that is transferable. The update must be done at a KIA/Hyundai dealership. Stop thinking that oil will make a difference, it will not.

 

[mpack88]

I've noticed on my Taurus that after 5k my TBN gets low. The 3.5L duratec has no fuel contamination problem. I think the RGT is a good oil but not for extended use. Blackstone told me to keep my oil changes around 7k. I keep it around 5k.

 

[MParr]

Having the updates done on the Theta II does not guarantee that the engine will not fail. Not having the updates done does not mean that the engine will fail. The 2.4 Theta II has 13:1 compression ratio. Run that joker on 87 octane and in the Eco Mode and you are asking for trouble.

 

[Resyek83]

Sorry late getting back to all of you, I should have mentioned I'm a Master Elite Kia technician at the local dealer so I'm well aware of the recall and all its "nuances", been with Kia for 10+ years now so these cars are like the back of my hand. I actually bought this car last year, so the engine issues I knew well ahead of time, ended up getting a great deal on it due to the mileage and the negative reputation the engine platform has.

Somebody mentioned hooking up a scanner and checking fuel trims, believe me I've been all over the data list with the KDS scan tool and I dont have any fuel trim issues and the car runs absolutely perfect otherwise. Fuel mileage in the low to mid 30s on the hwy, etc. I do run it hard at times just because.....'TURBO'.....but seriously though I'm starting to believe the fuel mapping is too rich at times, the last run actually had more fuel in it than the first and it was during the hotter summer months when I drove it a little harder since the roads werent icy. Maybe I'll get a bug up my bum and put fuel injectors in it someday but I'm not sure it would solve anything. Of course, the 2.0T is the lesser-common engine configuration as most have the NA 2.4, so its hard to find a lot of UOA's to compare to, but I have found several other instances of 5%+ fuel on other 2.0T models. I'll definitely check back if I find anything.

EDIT: also I hate ECO mode because it just de-rates the boost output on part throttle so I don't use it. 87 octane fuel per owners manual.

 

[FZ1]

Different strokes. I think the best "fix" is the 3,000 mile oil change you are doing. The wear numbers look good and the exit vis is ok. Perhaps, drive it more easily if you want it to last. jmo

 

[4WD]

I've noticed on my Taurus that after 5k my TBN gets low. The 3.5L duratec has no fuel contamination problem. I think the RGT is a good oil but not for extended use. Blackstone told me to keep my oil changes around 7k. I keep it around 5k.

Yeah - Carbon Steel posted his RGT where TBN is 2+ after only 5K …
got mine on clearance so will be guilt free doing 5K in same Pentastar

 

[Accent Abuser]

View attachment 82592

I recently performed a couple UOA's on my 2012 Kia Optima 2.0T. Both intervals of around 3k miles or so. This is one of those dreaded "theta 2" engines that arent known for durability, so I havent gone much farther than that. The engine is all original, vehicle is all completely stock. I have a fuel dilution problem, I replaced the high pressure fuel pump after the first test and had even more fuel in the oil on the second test, so that pump probably wasnt bad, I guess I'll keep it as a spare. I've heard of fuel dilution on some of these GDI engines but you'll also find some out there that are just fine. My daily commute is about 7-8 miles which probably counts as short trips, there's 4 or 5 stop signs along the way 40mph top speed, but I get out on the weekends for longer trips too. Should I be switching to a 5w40 for some extra safety margin on the oil viscosity? Its thinning out to a 20w after only 3k miles, and the TBN is getting eaten up just about as fast. On the plus side, my wear metals look good.

If temps are above 0F I'd go 10w-40, a high viscosity, high HTHS (4.0 or greater) version like QSAM or Valvoline Maxlife. When it's super cold, M1 0w-40. I wouldn't go 5w-40 unless you want to spring for something such as Redline or go with an HDEO, many of the majors 5w-40 is subpar to their 0w-40. Stick to 3k.

 

[Blinker]

Having the updates done on the Theta II does not guarantee that the engine will not fail. Not having the updates done does not mean that the engine will fail. The 2.4 Theta II has 13:1 compression ratio. Run that joker on 87 octane and in the Eco Mode and you are asking for trouble.

No it’s not. The compression ration is 11.3:1 for the naturally aspirated Theta II GDI. The 2.0T Theta II is 10.0:1 I believe.

 

[scm]

Sorry late getting back to all of you, I should have mentioned I'm a Master Elite Kia technician at the local dealer so I'm well aware of the recall and all its "nuances", been with Kia for 10+ years now so these cars are like the back of my hand. I actually bought this car last year, so the engine issues I knew well ahead of time, ended up getting a great deal on it due to the mileage and the negative reputation the engine platform has.

Somebody mentioned hooking up a scanner and checking fuel trims, believe me I've been all over the data list with the KDS scan tool and I dont have any fuel trim issues and the car runs absolutely perfect otherwise. Fuel mileage in the low to mid 30s on the hwy, etc. I do run it hard at times just because.....'TURBO'.....but seriously though I'm starting to believe the fuel mapping is too rich at times, the last run actually had more fuel in it than the first and it was during the hotter summer months when I drove it a little harder since the roads werent icy. Maybe I'll get a bug up my bum and put fuel injectors in it someday but I'm not sure it would solve anything. Of course, the 2.0T is the lesser-common engine configuration as most have the NA 2.4, so its hard to find a lot of UOA's to compare to, but I have found several other instances of 5%+ fuel on other 2.0T models. I'll definitely check back if I find anything.

EDIT: also I hate ECO mode because it just de-rates the boost output on part throttle so I don't use it. 87 octane fuel per owners manual.

I know it’s the Gamma, but I did get a UOA done before I had to turnaround and get a different ride (due to the addition of our first child, LOL) link here. My driving on that UOA was 60% highway/40 % city.

I want to say someone else on the forum came to the same conclusion as you did regarding the fuel mapping being too rich.

 

[LineArrayNut]

Imo 93 gas works best to stop the rich condition
My 2011 still is gas in the oil smell but less than when running 87. I have a tune on it and close to 128k miles. 5k mile oci 40 wts mostly.

 

[haggler]

As others have said, higher octane gas helps but short trips will still cause it. I would also try a Chevron concentrate fuel system cleaner, perhaps your GDI injector spray pattern needs cleaning. I change every 6 months and thats around 3-5k. I didnt use blackstone so I couldnt get a fuel number but my 100C visc did drop (11->9.8) in a recent UOA, though not as much as you (I have 2.4 NA motor). I'm now running Shell RGT 5w30 as well and I think it shears quite a bit more than other oils. I've seen RGT UOA's around here shear down to 8~ regularly. I'm not sure what you used previously but it might be worth trying a 10w30 or w40 full syn in another brand. On the other hand, you have pretty much normal wear so there is no critical need here if you maintain that OCI.