Has anyone experienced an immediate metallic sound from the engine on cold engine start up. It sounds like a loose timing chain or piston slap noise. It lasts for seconds only. Have not heard it until we got the cold temperature snap here in Pennsylvania with over night temps close to freezing. So could be 40 in my garage. There was a thread about the oil filter needing a anti-drain back valve, which mine has. So that is not the problem. It does not sound like a starter issue. It's immediate on engine start up and lasts around 3 seconds, and then goes right away. I can't imagine piston slap would only last 3 seconds. It really seems to be an oil pressure issue. Perhaps there is a hydraulic time chain tensioner that is the problem. I did an oil change for the first time since owning the car and used Mobil One, as recommended. Perhaps for winter I should go back to petroleum based oil. Any insight would be greatly appreciated. I thought about disabling the ignition and cranking the engine to build up oil pressure and then re-enabling the ignition and see what I hear when the engine starts. Wish there was a link to add audio to these threads. I'm going to try to record the sound on start up. Cheers.