I have a 2004 honda accord ex with the j series v6. A week ago, it started making a metallic tapping noise sounding just like lifter clatter but also purrs like a kitten at times it doesnt seem to matter what the engine temp is,the noise resonates more from the passenger side of the engine though,and does this 70 percent of the time.

 

welcome to the forum. your accord may need a valve adjustment. and what weight oil are you using, normal is 05w-20 mobil.

 

we have started to see a ton of the v6 engines at my dealership with bad camshaft lobes causing the valves to clatter. no huge fix for it besides putting in new camshafts and possibly new rocker arms!

other possible thing it could be is the timing belt tensioner...this is on the right (pass. side) of the engine and keeps tension on the timing belt. when these wear out (like a tiny oil filled shock) they clatter pretty bad and can also sound like that. look up what the tensioner looks like and you can run the engine and put your hand up inside and feel the back of the tensioner with your fingers from the right side wheel well (watch out for the spinning belt!)