jpohl402

My E63 recently started doing this...

At low speeds / low-mid RPMs --
OCCASIONALLY (when getting on gas in average driving) will make somewhat of a rattling noise (almost like marbles or tin cans hitting together)....
Sounds like it's coming from lower portion of engine
My initial thought was something to do w exhaust/maybe manifolds loose, etc

It is fairly noticeable

My one friend thought it was primary cats rattling/BB's inside coming loose

Another person in car today explained he had a similar noise on an Infiniti or something and one of the front calipers ended up being slightly loose....
It only occurs about 50% of the time....

Thanks

Fr33kn63

I had same problem last year. Dealer replaced both of my secondary Cats and as a precaution I made sure all of my heat shelds around the exhaust were nice and tight.
Loose marbles sounds just like what I had. At less then 50% throttle low speeds.

Soon after I modified my exhaust and just deleted them. Got them for sale anyone wants them. Brand new

jpohl402

Thanks. I will have this checked out....

intellilogic

Only thing I can contribute is that the sound is in fact abnormal. Where you say it is coming from is where the primary cats are.

Fr33kn63

they should be able to put a stethoscope up to each cat while under partial throttle to listen for rattle inside and should warranty replace any that are making noise. Thats how we figured out it was my secondaries. WOuldnt be a bad idea to have them start there, but try to be there when they do it as they can sometimes not hear things until you point it out.

MB_Forever

The car has fairly good noise insulation, and if you're hearing the sound from inside the car, it must be even louder outside the car. But you say it was not too loud. Have you considered maybe that the sound can be coming from inside the car maybe a loose clip somewhere?

VENOMNS

Where are you located... I have an ultra sound tool that will pinpoint it with in 10 seconds!!

jpohl402

Thanks for the replies guys....
Definitely outside the car

To Venomns -
although that would be great - I'm probably not anywhere near you
Omaha, NE

Let me know.... Thanks

jpohl402

It is becoming more prevalent & often now, I noticed it yesterday at 50mph.....
Have not had any time to diagnose it

But, I thought of the perfect way to describe it now.....
Like a diesel motor starting/running (glow sticks warming up)
That's exactly what it is......

Ckim1021

Does it happen when you press gas(at the moment you press gas)?
Do you hear when the window is down?
I think I have same issues with my car.
When I got a loaner car, C300, from the dealer, it also was making same noise. So I thought that maybe it is normal.

jpohl402

Yes when getting on gas......

jpohl402

Any other ideas ?

Ckim1021

I asked my SA about it but no real answers.
When I had a loaner car, 08 C300, it also made same noise.
My SA thinks that CA has low octane gas so it might be the reason for it.

I hope that someone will come up with good answers.

jpohl402

Thanks....
I know you asked me earlier if I can hear when the window is down - well I can hear this noise when windows are fully up-a/c on-music on

Interesting idea about gas, only thing I have around me (and use) is 91.....

jpohl402

Well I really believe the engine is pinging due to the usage of 91 Octane....
Any sure-fire way to tell this is the cause of noise ?
Thank you gentlemen.....

jpohl402

I want to make sure nothing is wrong w my car, any suggestions ?

MB_Forever

You can eliminate the gas factor by trying out some 100 octane gas in the car. Wait until gas is very low, then fill up at a 76 gas station that sells 100 octane.

jpohl402

Good idea.....

I don't even know of any in my area ?
Any of those gas websites could help (gas buddy or something) ?

markabcls55

on brand or units sold...check your PM

MB_Forever

Where are you located? If you contact VP-Fuels or Sunoco, they'll give you a list of the closest distributors to your area. You can contact them and purchase a small 5-gallon container or even a 15-gallon drum.

http://www.vpracingfuels.com/

http://sunocoinc.com/site/Consumer/RaceFuels/

100 octane should be more than enough to rule out the knock from bad fuel.... just make sure you fill up at least 1/2 the tank.

preston27

I have the same noise in my car. Did anyone find out what the noise was?

jpohl402

It is definitely pinging due to pre-detonation