Kura kura engine sound????

Hello all.

Fairly new addition to the group and I must say this is the best collection of knowledge and DIYers on the net. With that said I figured I'd share my 3 month ordeal with SOC and my poor '07 stock 5-spd LGT.

So about three months ago, at 92k km when gently accelerating or keeping a constant speed on a warm engine, I would hear what sounded like a gentle engine knocking sound between 2200-3000 rpm. On the first trip to the dealer, the service manager was stumped. This is an old timer that, IMO, is a guru when it comes to Subaru noises. His initial thought was a loose crankshaft bearing. Which translates into a replacement of the short block. But in order to do this under warranty he had to have a rep check it out first. So the regional master mechanic from SOC, came out three weeks later. I was not with him when he test drove the car but his diagnosis was normal engine and exhaust noise for a Subaru, been there from day one the car drove off the lot and is referred to, by the Japanese, as Kura Kura (that is how he pronounced it). When I heard this I blew a gasket. My bitchin to SOC that this noise recently started, and with support from the service manager, the regional rep came out three weeks later and with me in the car we went for a test drive. His response normal engine noise for a Subaru referred to as the Kura Kura. He said there was a study done on it and all 2.5L engines (turbo and N/A) with a manual transmission have had this sound since 1998. You don't hear it with the automatics b/c of the torque converter. I found this hard to believe as this is my thrid LGT 5-spd and this is the first time I hear this noise. The car has been maintained to dealer spec (Mobil 1 oil changes at 5-6k and always 91 OCT gas) I asked him to produce something in writing, and the rep said that was not possible as it is an internal document that can not be released. My response was produce the document or prepare to settle this with CAMVAP (Canadian Motor Vehicle Arbitration). Last I heard on Friday is that they are replacing the short block.

So has anyone heard of this Kura Kura noise? It is not the typical exhaust boxer rumble. Sounds like a rod knock but only between the 2000-3500 rpm in any gear when under gentle load.

Apologies for for the long story.