ML320 rattle engine noise

[Marc]

I have a 98 ML320 with 107000 miles on it.
It runs and shifts fine but the last week or so I'm hearing a rattling type noise when you shift into gear. Upon further inspection, when the car is in park or neutral, you will hear the noise just every once in a while at idle. If you shift into a drive gear forward or reverse, you will hear the noise all of the time at idle. If you step on the accelerator the noise goes away. The noise seems to be coming from the upper front area of the engine. Only thing I can thing of is timing chain. I also have an 83 500sl when it needed a timing chain it just rattled at startup until it had oil pressure. This does it all the time at idle.

I would appreciate any thoughts or direction to a related post.

Thanks

[Marc]

Could this be the lifter noise I'm seeing discussed here?

[rrodz]

It could also be your cats, there is a recall on this.

Rene

[Silver99ML320]

Could be your exhaust manifold.

A/C Fan Wiring, Rattling Noise, etc.

[3POINT]

This Noise Could Be The Crankshaft Pulley. The Big Pulley At The Front Of The Engine. The Rubber Center Self Destructs And The Pulley Rattles Around. There Is A Service Campaign On This Problem.

[outofspec]

I thought I'd reply to this old thread to document my solution to "ML320 Rattle Noise".

I have a 2005 ML350, made a bad metallic rattle noise when put in gear; D or R. Read through many many threads, and pushed me to the conclusion that I must have a bad cat converter.

Upon inspection, I found that both O2 sensors had backed out of their threads and the sensors and the washers were rattling. A pleasant surprise. The vehicle has 140K miles on it, and the sensors looked original, not sure if that's possible. I bought it with 95K.

Anyway, any future rattlers may benefit from this info.