Load banging noise
 

Just now I was driving, and on a heavy acceleration, when I reached around 70MPH I heard a sort of backfire noise and a loud rattle from the exhaust. I put the car in neutral and stopped at the first place I could. On idle there seems to be a banging noise like some metal parts are hitting against each other, and when I give it some gas on neutral the banging noise keeps the same noise level, only the frequency increases. I am not sure exactly from where the noise is coming, but I can hear it most from underneath the car, so I am not sure if its from the exhaust or from the transmission/engine. Any ideas? Every month something bad is happening!

2004 Boxster S, 60K, just installed new clutch.

DO NOT DRIVE THE CAR!!!!! Timing chain may have went or IMS could have gone. Unless you can absolutely tell it is exhaust DO NOT DRIVE! Keep us updated.

Called my mechanic, but he can not make it today (its a holiday over here), and he wants me to record the sound and e-mail it to him. Is it at least safe to start the engine?

I wouldn't start it. The first thing i would do is take out the oil filter and see if there is any metal in it. If there is any metal, definitely do not start.

No, don't start it again.

AN update
 

Ok... so here goes an update. The mechanic managed to come and see the car and he told me that the noise is something external to the engine.... he is thinking it might be the belt. Will take the car to him tomorrow morning to troubleshoot further.

Video
 

With the mechanic on site, he needed to start the car briefly to identify the noise, so I thought might as well make a video to have it recorder- here you go.. Porsche Boxster S engine noise - YouTube Let me know what you think, you can hear the noise especially when i increase the RPMs.

Please keep us posted. I'm thinking about you Man. Hope for the best.

I hate hearing this stuff.

heh i wonder if I manage to go to sleep tonight... the fact that the sound is external makes me feel better somehow, but still im dead worried. Its the loudest at the right rear wheel well.

Hm, sounds awful but that the engine idles and you can rev it is, imho, a good sign. I'd open up the engine cover behind the seats, gives you access to the serpentine belt and all that is driven by it. My guess it's one of the components on the serpentine belt that has thrown a bearing.

Its the SYNCHRONOUS BELT ! Nothing major.

Whew glad to hear. A drop in the bucket of bad things that could happen. :)

Sweet ! Glad to hear that. :cheers: