That's good to hear. I've got 30k. The info on gdi engines all points to gradual build up of carbon on back of the air intake valves because there is no gasoline vapor allowed to enter there to keep them clean. When the build up becomes so much as to block air intake, the engine performance starts to exhibit stumbling, hesitation, poor gas mileage. The expense to deep clean them is several hundred dollars. Doing periodic gdi service with products like crc gdi cleaner avoids the teardown. I'm 75 and this is my first gdi engine. Can't afford that kind of expense. CRC treatment is $12.00 and a screwdriver. There may be a shortcut by spraying thru the pcv valve. That's why I am asking. Good luck with yours. I'm real happy with mine.
I don't think Niro requires this service but yes, you should be able to spray into the PCV hose but you will have to stuff something around the CRC spray hose because an open PCV system will be a major vacuum leak and the engine will not run.
Oh, one thing that I forgot to mention. ALWAYS use good quality gas with a direct injection motor. Poor quality fuel can increase valve deposits. My mother-in-law and my wife neither understand why I always get gas from a local Shell gas station when I could drive 5 miles down the road and get gas at a no name gas station for $0.10 a gallon cheaper. Even after explaining to them that it will lead to more service being needed sooner, they ignore me. Pay a little more now, or a lot later.
There are some with the opinion that the CRC spray type treatments do not do much of anything to remove carbon buildup. If media-blasting is needed to properly clean cabon buildup, what is a spray going to be able to do without any physical agitation?
FYI: I bought a can, but never got around to using it on my 2011 Sportage SX with turbo GDI engine. Just traded it in with 105,000 miles and it still ran perfectly. Also had a 2009 Mini Cooper Clubman with the 4 cylinder GDI turbo engine, and that was fine too. I would be curious to see what the back of the valves looked like on both vehicles, but they still ran fine after 100k miles. Of course I always use Chevron gas, which has good additives/detergents so that probably helps.
I have had several GDI engines going back quite a few years. I started with a mazdaspeed 3 in 2008, a few hyundais, a 2017 kia sportage SX with turbo engine and now the niro.
What I can tell you through this experience, as long as you use good quality gas, and oil, and do the regular maintenance on schedule, buildup won't be a problem until well past 100,000 miles