hi,i have a v6 3.0 with 105000k or 600000miles.
i have what sounds like piston flap clicking/knocking noise when eng cold.
when warm it goes away.the dealer at the last inspection said it's normal/common.comment was it's designed loose....has anyone ever noticed hearing this sound.it sounds like old school v8 loose bottom end at start then just goes away.
i run the car with 5-30 synthetic.
thanks in advance for whoever answers.

 

Are you sure it is a piston slap? It would go away when hot. If you get a long screwdriver and put it to your hear, out it at different place on the engine and listen where the noise come from. You can also buy a "mechanics stethoscope", to hear better. It could be your valvetgrain, bearing, exhaust leak....etc. Find where it is from.
Dayz

 

thanks dayz,
dealer and everyone agrees it's piston slap.when it's warm it does go away.
i have 5w30 cast syntec in it,(dealer reccomendation).
curious to try a differant oil and type.
thanks for the reply.will do the screw driver trick.
frank