What is Kia's official word on what appears to be a design fault with their engine?
How is Kia going to provide 7 years of warranty on an engine if it is going to cake up with carbon on the inlet values?
I have my first service next week and I will question the service centre about this and what is the plan to keep the carbon to a minimum.
I also wonder about the pictures in the marketing material that these products use. Did they use particularly bad examples of carbon build up to sell their products?
This is not a new problem. It exists on basically every direct injection engine and has been happening for 10+ years. It doesn't really factor into warranty claims because it doesn't harm the engine beyond reducing horsepower and efficiency. It's more pronounced and affects the engine more in naturally aspirated engines as opposed to forced induction engines. It has to get very, very, very bad for it to cause a misfire or any problem that can be diagnosed with a computer.
On older naturally aspirated Audi you could see a sizeable loss in horsepower (10%+ in some cases!) from carbon buildup. See an example here of how bad it can get.
European Auto Repair in Green Brook Township, NJ Specializing in Oil Changes, Brakes, Engines, Transmissions, Tires, & More.
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I don't know how KIA will handle carbon build up in a performance car like the Kia Stinger, but sometimes you could get Audi to do a walnut blasting under warranty to clean the valves, particularly if it got so bad that it caused misfires or a check engine light.
I don't expect a forced induction engine like a
3.3TT to have much trouble, if any, with carbon build up. Just because there is carbon on your valves doesn't mean it is having an appreciable effect on your engines performance. I'm not saying it will have no effect, but it's usually not as bad as people imagine when they first see pictures of their valves that have some discoloration and buildup. If it's as bad as the link I posted, then yea, you need to clean it.
The good news is that if you go to a shop that does walnut blasting they can clean your intakes for a few hundred bucks. It's not that hard. They remove the intake, hook up a machine to the intake runner and blast the carbon off the valves with walnut particles. It's definitely worth the money to pay a shop to do this as opposed to trying to clean it yourself.
Also, additives and all the quick fixes people like to talk about usually aren't that effective on caked on buildup. There does seem to be some truth, however, to getting your engine very hot every once in a while (high load + high rpms).
