I have a 2012 Malibu MXZ with about 150 hours on the Indmar 6.0. Last summer at the beginning of the season I switch to synthetic oil.I heard a light tapping coming from the engine. I quickly switched to a thicker synthetic oil. When it continued, I went back to conventional oil. The noise revs up with the engine and doesn’t go away with higher rpm’s. I know it’s not a rod knock ( i’ve felt that pit in my stomach before) But it seem to be coming from the valvetrain. I took the boat to boat masters in Livermore, a “ certified Malibu service shop”. They remove the valve cover and valvetrain from one side and said everything looked good and they had no idea what was wrong with it. I paid them $350 for the tear down and put it back together myself changing the needle bearing rocker arms to Bronz bushing trunnions. I took it out last night and I still have the noise. Has anyone had any experience with something like this? I’ve been reading that a bad lifter will sound like this, but my engine is so new. Oil has been changed at least once if not twice a year and is very clean. I’ve never seen any metallic flakes in my oil and it’s been doing it since the beginning of last summer. I’ve been out every weekend last summer running it at 4500 rpm all day and it still runs great. Any advice, recommendations, or suggestions would be appreciated. I’ll try to upload a video..
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