IMHO, buy and use Liqui Moly 2037 Pro-Line Engine Flush before spending $$$.
Add to oil right before oil change, idle engine for 15 mins, dump and change oil and filter, I'd suggest a High Mileage oil after the flush to clean up the softened up carbon build up even more and to rejuvenate seals to some degree. Also use Techron or another similar product in gas tank. Replace PCV if you want, they are cheap and easy to replace, BECK/ARNLEY 0450405 {267403C200, 045-0405} is only around $5 at Rock Auto and they are good, often repackaged OEM parts.

 

I put Lucas fuel injector cleaner in my cars every oil change .

 

Give this a gander. Applies to models starting 2014 I think.

How to prevent carbon buildup using CRC intake cleaner

The direct injection system in Sorento engines is fantastic for fuel economy/efficiency. But the downside is that carbon constantly builds up on the cylinder valves (since no fuel comes in through the air intake to clean the valves, as it did in older fuel-injected engines). The way to combat...

www.kia-forums.com

 

If its running fine. Leave it, or you'll regret using those additives.
Using name brand TOP TIER gas is the simplest action you can do as it cleans and is much cleaner fuel.

Note the carbon is not anywhere where the oil has access nor gas. Its in between. Read up on it if you like. But stay away from any of armature solutions they'll wreck you engine and you're to blame!!

 

Wow its amazing you made it this far. You must be using a clean premium grade of fuel. In any case here is where i would start.
1. A good dose of fuel injector cleaner. Lots of good brands including Techtron [dealer recommended] available at Walmart for about $8. Also STP high mileage fuel injector cleaner.
2. Then add a full can of Berrymans B-12 in full tank of gas. In fact I would do this for two tanks of fuel.
3. Next will be to attack the accumulation of carbon on the back of your intake valves. It's not difficult to do you just have to follow direction on the can. Spray can version of SeaFoam. Again from Walmart about $8 bucks

This will be a good start, After that a good maintenance schedule is recommended and that is going to be something of a personal preference. In every tank of fuel I add 4 oz of Marvel Mystery Oil + about 3 oz of fuel injector cleaner. Before every oil change I do a Techron treatment as recommended in my manual and by the dealer. My Kia is running just fine. That is what I do but everyone will have a differing opinion A few bucks spent at Walmart to me sounds a whole lot better than $1000 at dealer. Have a great day.

 

Wow its amazing you made it this far. You must be using a clean premium grade of fuel. In any case here is where i would start.
1. A good dose of fuel injector cleaner. Lots of good brands including Techtron [dealer recommended] available at Walmart for about $8. Also STP high mileage fuel injector cleaner.
2. Then add a full can of Berrymans B-12 in full tank of gas. In fact I would do this for two tanks of fuel.
3. Next will be to attack the accumulation of carbon on the back of your intake valves. It's not difficult to do you just have to follow direction on the can. Spray can version of SeaFoam. Again from Walmart about $8 bucks

This will be a good start, After that a good maintenance schedule is recommended and that is going to be something of a personal preference. In every tank of fuel I add 4 oz of Marvel Mystery Oil + about 3 oz of fuel injector cleaner. Before every oil change I do a Techron treatment as recommended in my manual and by the dealer. My Kia is running just fine. That is what I do but everyone will have a differing opinion A few bucks spent at Walmart to me sounds a whole lot better than $1000 at dealer. Have a great day.

We are at 105,000 and ours runs like new. I don’t think it is all that amazing…. Run top tier fuel more often than not and just drive it. I think people make carbon issues way worse in their minds than it is in reality.

 

At 100k miles, gdi engines not proactively maintained by using top tier gas (or periodic additive detergents) and shorter oil change intervals (think of severe maintenance schedule) will have tell tale signs of carbon deposit build up—loss of power, hesitation, increased fuel consumption, among others. If not treated or repaired (fuel injectors and intake valves) further repair will cost more or worst! $1k treatment/repair, unless there is a question of good maintenance (using severe schedule), is par for the course at this juncture (when most chemical treatments will have minimal effects to the already coked up and hardened deposit), imho! You may also want to google this further. That is, if you want to keep your Sorrento. Just my 2 cents. Thanks.

 

Man I'm hopping mad myself, I got a lil 2016 Sportage ( the cheap one ah Economy model ) it's got a tad over 35,000 miles, I've replaced the front drive tires , & did a driveway set of Disc Pads . Do a lot of congested area driving so on & off the brake pedal , I'm not going for any record in most MPG Ever in a Sportage , I'm driving cause I got places to go ppl to see & things to do . An swear every dang time I get stuck behind some Mini Van thing that's going 20 MPH below the Speed Limit an the length of 3 football fields behind the car in front of it . An Good Lord don't anyone make a lane change next to them , or a traffic signal several blocks away as they will be on the brake pedal shutting that thing down , I'm all for Defensive Driving but to quote one of Our Great Statemans & Current President --- Come On Man --!!! . 🤔🤣.... Personal I dump a bottle of Seafoam in the fuel tank once a month . When I get to that 100,000 mile mark I plan on dropping the Intake Manifold an taking a peek in there to see what She looks like . I see where other MFG have started putting a Second Injector per cyl to combat the effects of GDI , It was a know problem years ago from the get go with these type systems but the MFG didn't act on it at the time unfortunately.

 

Yeah, I think it was GM who did the 2nd injector mod to allow programmed flushing of the valves. Kia's had it for some time and if there were a lot of failure due to the existing design we'd have heard about it. If you don't have codes or driveablity issues then leave it alone. Kia said not to do it as a routine somewhere as well. TOP TIER gas is the best to used as well as Full Synthetic oils, and that oil has become mandatory for in warranty vehicles now!!

 

When you guys say "top tier" gas you are saying brand name gas, not higher octane gas?

 

Apparently the oil pulled into the intake from the PCV valve can add to the problem since it becomes part of the air that flows past the intake valves. There's at least one separate thread on this forum talking about using a catch-can to reduce this problem.

 

Yeah but if the engine is as designed without a defect it shouldn't be creating a problem. Kia would have addressed it. Whats happened the the ones which benefited from the mod is unclear. Other than its a 4 cyl issue.

 

The gdi engines in the early 2000s were plagued by carbon deposit build up. The newly designed (around 2014–not exactly sure) was modified so that the intake valves are somewhat exposed to fuel to mitigate this issue. Again, it is not a cure all answer to the problem. New oil formuation has been introduced to help with LSPI (Low Speed Preignition)—a byproduct of fuel and oil mixture combustion in the chambers that contributes to carbon deposit formation. This gives emphasis to the importance of oil change intervals. Oil does not only serves as lubricant but also as dispersant, coolant and detergent. The longer it stays in the crankcase, the more sludge it builds that circulate as vapor (PCV designed) and turned into carbon deposits in the intake valves. Along with other maintenance items (prevention is the name of the game) such as engine filter, spark plugs and yes, even coolant (it optimizes engine temp—too much heat kills oil). Thanks.

 

Unfortunately, Kia says a catch can violates the warranty.

 

I've not seen any official confirmation of their position on catch cans, and have heard that some dealerships accept that it does not effect warranty and other dealerships say it does.

The ones I have on my Ford Edge and Mustang are very quick and easy to switch back to stock if they should ever need a visit to the dealership.

 

I have been through this with my dealer. I even provided the name and model No of the catch can I wanted the dealer to install. The dealer however refused to install one and said in no uncertain terms it would violate my warranty.

 

Obviously a dealer wouldn't install a non-Kia modification.

 

There are tons of these GDI 3.3L out there from Kia and others. Currently no records of failures due to GDI design or carbon in them. Kia as others such as GM would have made changes after the initial year builds which we don't have. Finger's crossed anyway

 

Except that Kia has quietly added an auxiliary injector to the fuel system of newer engines to specifically clean the back of the valves, somewhat the same as many manufacturers are doing.

 

@tomm4416

Which year and engine are modified with that injector mod.

 

The V6 in the Telluride is modified that way and there is a video posted on here somewhere with the video from Kia promoting this "new" technology. It was posted under one of the discussions about this topic.

 

That's a 3.8L engine.
Thx

 

Okay. Not sure what difference that makes as engine size has nothing to do with carbon buildup from GDI only systems. It's a new motor, developed by Hyundai/Kia for use in their vehicles which incorporates newer technology to address a problem. Rather than roll it out to their existing line (perhaps acknowledging a problem they would just as soon not), they are perhaps going to use that engine in more vehicles while developing smaller displacement ones with the same technology. I don't know but obviously Kia, like Honda, Toyota and others have recognized that not cleaning the back of the valves with fuel is an issue and perhaps only an issue under certain circumstances like not allowing the vehicle to fully warm up and not driving it at fairly high rpms for any length of time. But, it's an issue that may or may not affect any particular vehicle depending upon driving habits, oil used and regularity of maintenance. For those of us expecting to get well over 100K out of our vehicles, pumping a can of CRC through every 10-15,000 miles is cheap insurance (or maybe just cheap peace of mind).

I have always suspected the carbon buildup is mostly limited to vehicles driven in short cycles, never truly reaching operating temperature. Since I started monitoring trans and oil temps, I've come to realize that full heating of the oil does not occur until a good 15 minutes after coolant temps have stabilized and although not relevant, trans temps are at least 10 minutes behind coolant temps as well. Essentially, the car must be driven 25-30 minutes for all systems to have reached optimum operating temps and to have the best chance of avoiding carbon buildup anywhere. And I drive in the desert with ambient temps often around 100 degrees. I also believe that the old fashioned Italian tuneup is good for these very low revving vehicles.

 

From what I have been reading, the oil you use and your driving habits are the biggest factors in this carbon buildup if you have an older style GDI engine where no fuel reaches the back of the valves. My understanding is that the fuel is NOT sprayed on the back of these valves in our cars. The video I saw posted in this forum earlier this summer did not answer this question or address this issue.

From the Bob is the Oil Guy forums, oil with a low NOACK is better for our engines. Lots of reading over there, here is just one thread: https://bobistheoilguy.com/forums/threads/low-noack-oils.312658/ Look up others over there for a discussion on this value and how it contributes to carbon buildup. Synthetic oil alone is not the best indicator of low NOACK.

Low NOACK scores have less oil evaporation that gets circulated, which contributes to less carbon buildup. I did most of my reading on this a few years ago when I had a GDI in my 2014 Rondo. I have also read that having the engine properly warmup will also help, but don't have any proof for you on that but just speculation and info from sources trying to sell cleaners, etc. But if you take frequent long trips that might make this a lesser issue for you.

I'd actually love to see info that this 3.3l engine in particular has gasoline sprayed on the backs on the intake valves. It would make me feel much better but I have not seen any info that shows this.

 

I am driving a 2019 Kia Sorento LX V6 all wheel drive. I installed an oil catch can and a new PCV after using seafoam spray and it special nozzle that comes with the cleaning and lubricating item. After using the seafoam spray I immediately change the oil and oil filter. I also put in a new positive crank case ventilation valve and then hooked up my hoses from the output of the positive crankcase ventilation valve to the oil catch can assembly and back to the connection that goes to your air box intake just Upstream from your butterfly valve. I had to remove the air scoop the battery the air box that contains the air filter my mass air flow sensor segmented hose. As many can attest riding in the car, the idle speed smoothness and the acceleration is just as good when it was brand new. Once a month you need to use gum out STP Techron or berryman's B12 in your gas tank to keep your high pressure fuel injector nozzles clean and up to Snuff.

 

Once a month let your tank run almost empty and then fill it up with ethanol-free gasoline. Then add Techron techraline to your gas tank and make sure you take a long 30 to 40 mile trip at highway speed to get your transmission and your engine up to operating temperature. This will help keep both your injectors clean and the back of your valves clean for a lot long time.

 

I looked at doing an oil catch-can on mine. Saw some install instructions, but way too complex for me!

 

I have a 2017 Kia Sorento that had carbon build up, took it to Kia had them do the $500 clean and still didn’t fix it from eating oil, I was adding about a quart a week, now I have a misfire on cylinder 2 and loosing compression most likely due to carbon build up and either valves are seized or bad rings. What can I do without replacing the engine or head??? Can I pull valve cover off and put some elbow grease and brake away the carbon deposit?? Also is there any kind of recall on this where I can get it replaced for free lol??

 

I believe the gold standard is taking the top off and walnut-blasting the back of the valves.

The $500 clean I'd guess was that intake spray, I hear it's best left as a preventative measure than as a mitigation.

Are you certain it's carbon? I don't think I've seen burning oil considered a usual symptom, I'd try the PCV valve first, easy to do on the 2.4. Any powertrain warranty left? I assume no but if yes you can try to get them on oil consumption assuming you aren't driving >1000 miles weekly.

Otherwise you can run it until it seizes, add used oil and hope it's covered. The bottom end is covered under the lawsuit warranty (assuming you indeed have the 2.4) but I don't think compression or any other issue would count.

 

Can I pull valve cover off and put some elbow grease and brake away the carbon deposit??

You’d have to take the intake manifold off to get access to the back side of the valves, it’s not too difficult on these 4 cyl engines. Then you can use carb cleaner and some picks and nylon brushes or whatever you have to get the carbon off.

Carbon buildup on the intake valves probably isn’t the cause of your oil consumption though. It’s often caused by carbon clogged piston rings, particularly the oil control ring. You can search how to do a “piston soak”, that can sometimes help reduce it.

You can also change the pcv valve, it’s cheap and easy enough to replace and could help, but it’s more than likely the carbon clogged rings.

I was adding about a quart a week, now I have a misfire on cylinder 2 and loosing compression

Try swapping the coils around and see if the misfire follows, check the plugs too, if it’s been burning that much oil maybe they are fouled. Hopefully it’s as easy as that and not a burnt exhaust valve.

 

I have replaced all plugs, I swapped coils from one and two cylinders and the misfire didn’t move. I pulled the plug and it smelt like fuel but idk if it’s enough? I also have not yet confirmed if loosing compression but will soon. I already have taken the valve cover off and top looks really clean. If there is carbon would I see it up top or only below the cams? Also everything moves smoothly when I manually turn crank. If it is carbon clogged rings would that cause a misfire and or loss of compression?

 

You’ll only see the carbon build up if you take the intake manifold off. I think your next step should be a compression test, if it’s low you can dribble a little oil down the spark plug hole and see if it comes up, that will tell you if it’s going past the rings. Also a leak down test will let you know where it’s going too.

 

This why after purchasing mine with 8

This is why after buying my 2019 Sorento LX V6 AWD (w/80,500) I installed an oil catch can system. Every oil/filter change it gets emptied out. Berrymans fuel treatment once a month. 179,00 and no rough idling during cold weather.

 

If you’re a somewhat competent home wrencher, you can walnut blast the intake valves. I’ve done it on my Focus ST and did a write up on the process…had fantastic results and it took an afternoon.