I got my wagon with 69000 its @91k im hoping to keep it another 5 years. I do all preventive maintenance. I seafoam twice yearly i do not plan to clean valves manually. I dont feel its worth the effort. May be if it was a 8 second car. Where every liitle bit counts, i might. For a commuter car, my apr 2+ wagon or my vr6 cc. Unless the valves start to stick or not seat properly they're not getting done. Ive seen plenty of engine internals. I've installed plenty of heads on plenty of fuel injected cars. Direct injection not so much. But even in 2013 the combustion cycle & basic operating principles of an engine remain the same. I dont think you can sell me on manually cleaning valves. Bent over in front of the car for 2-3 hours versus removing head and having head on work bench.
Thats like saying the cam follower shouldnt be checked as a wear item.........
Again its well known knowledge, and readily available that the valves need to be manually cleaned. Either by scraping or media blasting.
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