When my outback is cold, the engine produces knocking noise, which I cannot clearly assign. In idle they are very quickly over (approx. 5sec), but as soon as I put on R or D, you can hear it clearly again. When the engine is warm, the knocking becomes significantly lower. It is then only very easy to hear in idle, as soon as you give some gas you can not make out the noise under the other engine noises. Come on from the left side, cylinder No. 1. No I don’t know if this is a valve setting or a piston tipper. I exclude bearing damage, you would hear it all the time. The engine is otherwise silky soft, has no oil consumption and the power is also right. As far as I have read this in English forums, a piston tipper is by no means unusual at Subaru and no reason to worry, it is simply annoying. Greetings, Zeph