I have the dreaded piston slap in my leased 2000 outback. I was planning on purchasing it at the end of the lease. I have taken it to the dealer three times and each time I have been told that it is normal. Yes, after completely warming up the noise goes away. This usually takes 15 minutes or so. I can't believe that there is not some damage taking place inside the engine. The car only has 49K+ miles it. Should I be taking it through the Subaru appeals process? Have others gone through this?
If it's still on warranty, why not give it a shot? I have a 99 Honda Civic (I'm here because my daughter has an Imprezza) and it also has what has been described as piston slap. However, when I mention the word to some mechanics they look at me like I'm from Mars. Can you describe what it sounds like and if the air temperature has an effect on it? Mine is worse the colder it is. In the warm summer months, (outside temps above 60F) I don't hear it.
A Honda tech once told me that excessive carbon buildup could cause it. So I used one of the commercial carbon cleaner products; the type that gets sucked through the intake manifold via a vacuum port while running the engine. After doing so, the noise disappeared for about six months. However, another tech told me that I could damage the O2 sensors and the catalytic converter if using these products regularly. (I had an O2 sensor fail last year). So I haven't done that anymore and now the engine has 118k miles and every winter the racket gets louder during warmup. Sounds like a diesel. It would be hard to convince me that it is not causing internal damage or excessive wear.
Why go through the aggravation of the appeals process with a leased vehicle? If it were mine, I'd endure the problem for the duration of the lease and then turn the car in and find another vehicle. I would try to get some documentation of the "normal" determination from the dealer so that he doesn't try to stick you for improper maintenance or something at the end of the lease.
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