Just noticed this after finding a split plastic radiator tank top (just in front of the top rad hose (I think it is a seam area) I didn't lose much coolant and engine did NOT overheat, so I don't think it is directly related.
What happens is that when you rev the engine and hold between 1750-2000 rpm you hear a light knock sounds like its coming from near the middle of the engine block but not sure, as so as you have the rpms below or above that range you no longer hear the knock.
Engine has been well maintained never been low on oil, proper oil change intervals. 129k miles.
This sounds like a case for Tegger.
What happens is that when you rev the engine and hold between 1750-2000 rpm you hear a light knock sounds like its coming from near the middle of the engine block but not sure, as so as you have the rpms below or above that range you no longer hear the knock.
Engine has been well maintained never been low on oil, proper oil change intervals. 129k miles.
This sounds like a case for Tegger.