Team-BHP - 2020 VW Polo 1.0 TSI | Engine failure & breakdown | Cylinder damage

As regards to the problem of the owner and the solution, the manner in which it was conveyed to him, in its casual lack of assurance, there seems to be a generic response from VW about the replacement of Engine Head as that is the most common solution applied to such engine failure situations. The Humble Mechanic YouTuber/VW mechanic informs about the VW protocol in these situations. The fact that VW is not going for a complete engine replacement indicates that the root of the problem lies at the intake valve region of a particular cylinder often caused by carbon buildup due to crankcase ventilation system throwing up blowback gases into intake system. Direct Injection engines produce very high NOx emissions, so this Crankcase Ventilation System is required to recirculate the blowback gasses for producing cleaner emissions among other concerns like reducing crankcase pressure.

Intake Valve carbon buildup is the most common reliability concern of direct injection engines and hence after market solutions like Oil Catch Cans are used apart from other intake valve cleaner treatments. Strangely it is at idling when the intake valve get the highest pressure from Postive Crankcase Ventilation (PCV) Valve. Ironically some theories suggest that redlining your car, Italian Tuning, will rather get rid of this carbon buildup but only senior BHPians can enlighten on this. Anyone buying a direct injection engine vehicle should expect carbon buildup on their intake valve which would result in knocking at idling, reduced power and fuel efficiency and even worse emissions. That is a downside of these exciting engines so being mindful and proactive will only help. I know the Polo TSI owner did all his due diligence with service so I am not suggesting he was negligent/ignorant in any manner. He trusted what VW offered and put his money on it. He is not at fault driving 25000 km in 7 months either. I hope he can get a reliable solution with further warranty assurance from VW and share his future experiences with us.

I have booked an i10 Nios Turbo and that is the reason I had to educate myself on these GDI engines and their problematic aspects. For once I am excited that the Indian market will be mass flooded with direct injection turbo petrols in small affordable cars for first time buyers like me who have never even driven a vehicle but aspire for some performance and affordable excitement from their vehicles. I know it is very hard for the Polo Tsi owner to justify his purchase and to not be disheartened in this case but I feel any vehicle can suffer such a malfunction. Who knows it may not have arisen from whatever I have asserted above and it is indeed a manufacturing flaw. Even still direct injection turbo petrols and their manufacturing in India serves as a sort of technological leap in Indian vehicle manufacturing scene which could soon lead to further refinements in engine reliability, who knows maybe simultaneously port & direct injected engines can sooner find their way into mass car segment adding naturally aspirated engines' level reliability to already great perfomance and fuel efficiency characteristics of a TSI/GDI engine. Who knows we may see some sort of superchargers too in these mass market vehicles to add to the low end response. I am forever optimistic. rl: