I have done a lot of reading on this. First, 03 with 50k miles and horrible piston slap. Tensioner has already been replaced. Dealer/SOA has agreed to replace 2 of the pistons. I am trying to get them to change all 4 to balance the motor.

Should I have this done? My concern is that major work like this will lead to problems down the road after the warranty is up. I tend to keep my cars for a long time. I can’t stand the noise. I also don’t think I could get rid of the car as is because of the noise.

Sounds like this is a known problem to SOA or they wouldn't be so willing to replace anything. They must know that there are two pistons that cause the problem and is why they are willing to replace only two. Yes, I would have them do it, hopefully they have a loaner car for you. If that doesn't fix it, then they will have to replace the other piston. It would be smart to replace all 4 at the same time, but they look at it as why pay for more then they need to.

Yup, only one side slaps. Two pistons would be fine. It was cold today and my Forester (132,000 miles) had a prettty good slap for the first three blocks. It's gone when it warms up and the oil test says no unusual wear. Havoline dino oil helps the noise and I've just learned to live with it.

Thats the standard repair, and so far everyone seems happy with it.

They only do two because i think (dont laugh at me) it has to do with the direction of the connection rod on the power stroke and gravity.

Which side are they replacing.

 

nipper