Clattering noise when cranked

[Rusty]

Just got my P5 with 37000 miles on it a few weeks ago. Once you get the hang of how they like to be treated, they really scoot through traffic.

A couple of weeks ago I spent a weekend with my car buddy test driving it. Hits 6500 with zero vibration. It's the smoothest balanced engine I have ever driven. (I am an old muscle-car dude though). We ran it on up to 7200 rpms maybe three times, still no sign of pain.

During my weekly driving I may hit 6k, maybe 65 three times a week. Never into the red paint though.

Now my question. Three times since we ran it hard that weekend, I have heard a clattering sound when cranked the first time that day. It lasts 5 or 10 seconds. The temperature has been in the 50s and 60s. I have yet to get the hood open fast enough to locate it (wife will assist me tomorrow morning). No change in engine performance.

Do you think I could have hurt a bearing or an end cap? How about something in the top engine?

Maybe I screwed up an external bearing (I hope like hell).

Thanks, Rusty

P.S this engine runs best a little before the temperature guage gets to its normal running position. What do you think about getting a 5 degree colder thermostat? Or would the computer override that? These things, I have yet to ,learn

 

[toucci]

check the heat shield on the exhaust manifold (the thing that says "HOT!")

When it gets really hot the first time, the screws might loosen and cause it to rattle

 

[Rusty]

Heat shield is tight, and of course it cranked beautifully this morning, while I was standing over it armed with a flashlight and my trusty old stethescope, with an old drill bit jammed in one end. Nada.

Thanks,
Rusty

 

[LZRBLOOP5]

It is most likely the "Cold Engine Rattle" that is inherent to the Emissions equipment (VTCS valve) on this motor for low temperature starts. It is normal apparently, and there is no fix, its a quirk that does no harm. There is a flash available at the dealer for vehicles under warranty, but I don't think that really does the trick. Just live with it, It happens to me every day.

 

[ARunto]

sounds like a normal cold rattle. as long as it doesn't persist when the vehicle is warm.