Guys, I did a search on this topic and found this thread. http://ferrarichat.com/forum/showthread.php?t=48859 However, I'm not sure if my noise is coming from a belt because it's a vibration and not a squeak. I also found the thread below, in which I myself responded. I had forgotten about that thread and I since have not yet identified the rattle. I don't have cats on my car so that could not be the problem. http://ferrarichat.com/forum/showthread.php?t=33892 So here's what I'm experiencing: whenever I start the car cold, there is a kind of vibration/rattle coming from the back of the car. I don't know how long it lasts because I usually drive away immediately after ignition. When I start the car warm, there is no such noise. Does anyone know what this could be? Also, if you are a 348 owner and you experience this same symptom, tell it here!
I did notice something like that when I first got the car. I had a check engine light come on after an engine detail. So I disconnected the battery, and then started and let it sit for 15 minutes. It helps the ECUs re-configure or something. Anyway, that when I noticed it. It would have trouble sometimes starting. I would stall every so often when I did it. Then it would idle roughly with a few rattles. It just went away after 10 or so starts. Everything has been perfect since. Doubt this helps you, I just wanted to let you know what I experienced.
It could be a lot of things. The typical vibration problem for a 348 is the flywheel running out of grease, but you'd first experience that when the flywheel was hot (hard starts, rattling, etc.), not when cold. I'd check the level of your tranny fluid. There's a little tiny dipstick on the driver side of the tranny down at the bottom. Could be low tranny fluid or contaminated tranny fluid or a new tranny fluid that is too thin. Another vibration/rattle problem that shows up cold is when some of the muffler bolts are loose...when warm, everything has expanded enough that you won't get a rattle, but when still cold, you will.
Also, do you hear the rattle when cold if you start your car with the gear shift in Neutral and the clutch depressed? Or do you hear it when you first shift into reverse? Or do you hear it no matter what when cold?
Thanks for your help guys. I always start the engine without using the clutch, so I'll have to try using the clutch. The sound always occurs when I start the car, which is in neutral. When I drive I can hear the sound also. I just had my transmission fluid changed, so that can't be it.
Hi, Dave; This is one of those problems that could be any number of things, and it's hard to go in any one particular direction using just an internet description, rather than hearing the noise myself. Just to narrow it down, is it possible that you are talking about the "gurgling" noise that 348's make on cold starts? This is the air injection system pumping fresh air into the exhaust manifolds to reduce emissions when cold. It isn't really a "vibration" in the sense of something that you could feel through the seat of your pants, and it isn't a "rattle" like two metal parts clanking against each other. But it's a very distinctive noise, heard loudest through the air intake ducts above the rear wheels. It goes away after the engine warms up for a few minutes. If this obviously isn't your problem, give us as much detail as possible on the symptoms, and we'll try to sort it out.
No no! Love the gurgling. That is a sound I know well. Here's how I can describe it maybe. Think of when you have your engine decklid open, and then you sort of slam it shut. After it closes, there is a metal vibration that lasts for a couple seconds. Well, it's that kind of sound. It's pretty persistent and consistent on cold startups and it lasts till the car is warm. I have a feeling it might be some bolts on the exhaust system as someone indicated above.
When I had a loose hearder stud it would vibrate at 4k RPMS and above, never at idle and wouldn't go away. Took me months to figure out what it was. But all cars are different; if you can reach yours put a wrench on them and see if you can tighten them. Mine was finger loose by the time I found it. ken
