I have an 02 S2K with 18K. The car has a rattle under the hood when you first start it in the morning. After about two minutes the sound goes away and runs fine. Could this be the cam chain tensioner or something else? Could this be normal? Oil was changed 300 miles ago, Castrol 10W-30 non synthetic. I have owned it for about a month and only drive it on the weekend. Starting to learn the cars personality. Any help would be greatly appreciated.
Thanks

 

When my cam chain tensioner went the rattling noise wasn't on cold starts. It would rattle when the car was already hot, and had sat for 5 minutes or so, and then restarted.

 

Mine did this...at first it was the catalytic converter heat shield (the rattle would stop when I applied pressure to it with my boot); and about 10K supercharged miles after that the cat material inside the cat converter broke loose and rattled.

If it's the shield, it's easy to check using your foot. to determine if it's the ceramic crap in the cat, remove unbolt it from the header and exhaust and give it a good shake. Mine sounded and felt like a mumified brain rattling around in a skull.

 

i have the same problem on my car and it happens mainly when i come to a stop at red lights ...... but after couple of seconds it goes fine. but sometimes it vibrates and then just switches off!! i have 98K on my mileage

 

I took another look at the engine this morning, I timed it this time. What seemed like two minutes was about 30 seconds. What I believe what I herd was valve chatter. Is this normal on cold starts with this motor? The sound goes away when the oil starts flowing and the motor starts to warm up.
Thanks for your replies.

 

I had the same problem. It sounds like it is coming from the valves but in actuality it is the timing chain tensioner failing and causing the timing chain to rattle. I recently took it to my dealership for this and they said at first it was low on oil and sent me on my way with me being comfused because I had topped it off a week prior. Well after dealing with their general manager and getting my oil changed due to them putting regular into my full syntehtic, they finally fixed the tensioner and the sound is gone. So yeah thats the first thing I would have them check. It's covered under warranty so it's a day fix if they can get the part quick enough.