GDI engine intake valve carbonization concerns

[Al Nonymous]

As a 2016 3.8 Coupe owner, I recently became concerned about the issue of intake valve carbon build-up on pre-2018 Gasoline Direct Injection (GDI) engines, described in this video:

Briefly, it goes like this: on a GDI engine, blowback crankcase fumes and contaminants recirculated back through the PCV valve into the intake manifold, tend to carbonize on intake valves because with GDI, fuel is injected directly into the combustion chamber, not into the intake port above the intake valves. Therefore, with no gasoline running over the intake valves to keep them clean and act as a solvent on crankcase contaminants, GDI intake valves tend to accumulate serious carbon deposits. Millions of cars today have GDI engines, but only in the last couple of years have some manufacturers redesigned them with two injectors...one in the combustion chamber, and another in the intake manifold, to help alleviate this problem.

The video advises owners of legacy GDI engines to take special precautions:
1) Install an aftermarket oil catch can between the PCV valve and intake manifold. It will eliminate up to 95% of contaminants from reaching the intake valves.
2) To keep GDI injectors clean so your engine runs cleaner with less fuel blowback, use only premium fuel with special additives, like Shell V-Power NiTRO+ Premium. Alternatively, use a product like Chevron's Techron every 4000 miles to help keep your injectors clean.
4) Switch from a 5w30 to 10w30 Group 5 synthetic oil with Noack oil volatility of 7 or lower.
5) More frequent oil changes, ie, every 4,000 miles.

The video ends by advising NOT buying a GDI-engined vehicle: either choose one with port injection, or one with newer GDI engine dual injection technology.

I'm not seeing anything in the Genesis Coupe forums, addressing this issue, and no service bulletins from Hyundai, either.
Has anyone installed an oil catch can on a 2016 GDI Genesis Coupe? If so, which brand, and how?

 

[NLJ]

Not an issue with most Hyundai/Genesis/Kia GDi engines. Just use Top Tier fuel.

 

[Al Nonymous]

Thanks for responding! Your assurance is helpful, but I wish you could explain further why you're sure this is not an issue, since on a GDI engine, top-tier fuel supposedly never touches the intake valves. My Hyundai service manager (who obviously stands to gain by selling more such profitable services) claims Hyundai recommends doing a complete Hyundai fuel system cleaning service for around $220 every 20K miles on their GDI-equipped cars. However, I haven't yet found anything in writing on any Hyundai website, confirming that claim, and haven't come across any service bulletins to that effect, either. Arguably, Hyundai might be wise to recommend this, to help protect their quality reputation as time passes and carbon deposits start causing serious performance problems in Hyundai vehicles. I read that a few manufacturers are only recently beginning to offer engines with dual injectors - a 'main' GDI injector, plus a supplementary port injector, to restore some fuel flow over the intake valves. Not sure if Hyundai is among them.

 

[Joepado]

Al nonymous Is entirely correct with his concerns. Using a top-tier fuel WILL NOT Prevent carbonization on the valves. The measures you describe can help, but they only delay the performance compromise from the carbonization. Ie , oil catch can techRon additive, top-tier fuel, etc. Please do not put 10W-30 oil in your engine, especially if you live in a cold climate. Genesis engines have Tight clearances and increasing the winter weight viscosity of the oil is not recommended. Don’t get me wrong, genesis makes fine vehicles, but GDI only, without port injection does require additional maintenance. Unfortunately, the technician is right and you need to get decarbonization cleaning periodically. Or suffer further complications and performance degradation over time. There are pictures on the Internet of very foul carbonization. I do not like dealers, but this is one service I would periodically get with the dealer, especially under warranty.