If it is indeed piston slap, there are a couple of options that you could explore. One is replacing the engine. The second involved a lot of tear-down and machine work. However, I would only consider these options if you absolutely cannot live with the noise. Have a reputable mechanic check the car out - including a compression test - if he believes that the car is mechanically reliable, and you can live with the noise, try not to worry about it. There are many 3.1L engines that have been experiencing the same issue.
Tuesday, September 27th, 2011 AT 10:36 AM