Bearing noise from Turbo? w210 e320 cdi

[too_juicey]

I have recently noticed a funny "bearing" type noise from my e320 cdi.

When parked and idleing, if it is reved to about 3k and released there is a type of rumble from the left side of the engine - where the turbo is.

I initially thought it was the timing chain, as thats what it sounds like, then I thought it was the air intake through the air filter, but it sounds almost 100% from the turbo area.

My thoughts are that it may be some bearings or something in there. It only happens when the car is hot, and there has been no power loss etc.

Any thoughts? Ideas? Tests?

 

[djb]

As turbos turn at 20000 rpm upwards & its bearings are small, any rumble is unlikely to be its bearing. Bearing wear usually anounces it self by the turbo whistling or whine.

However my 320 like all others I have listened to does have a sort of deep waffley type of noise in similar circs, one whichis normal I attrubute to the v formation. (sounds lovely in the garage!)

ps I assume yours is a v6

 

[too_juicey]

Hi Djb, sorry, mine is straight 6 e320 diesel.

 

[HERBIEMERCMAN]

rumbelling points to heavy load bearing bearings, camshaft, little ends, big ends. very rare on the merc engines but i know from friends that a small partile of swarf or sealant can obstruct oil flow in a journal gallery even on low mileage engines.

i agree that it does not sound like a turbo bearing issue.

if the hot engine exagerates the rumble, then your oil viscosity is not ramping up, are you using a good fully synth oil ? 5W - 40W.

you need to get a good opinion from your local inde, if a bearing breaks down you are looking at big buck repairs.

i have an e-300 td. and i experienced a loud rattle caused by excessive air in my injectors, no noise at tick over, but very rattly at 2,000 rpm. new bosch injectors resolved problem.
herbiemercman.

 

[Number_Cruncher]

>>reved to about 3k and released there is a type of rumble

Is it the overrun clutch in the alternator pulley?

 

[wireman]

Is it the overrun clutch in the alternator pulley?

Maybe try this:-

Take the fan belt off and do a quick rev it check, this will eliminate anything other than the engine and turbo as a source of your noises.

Don't over do it the cooling systems heat capacity will be severely compromised without the water pump running.
If your car has the little electric pump on its heater this pump will move sufficient water around your heater to provide enough cooling too allow running on tick over for quite an extended period (heater blower on full at max heat of course).

Have a good twist and tug at all the belt path components whilst the belt is off, listen and feel for iregularities as the parts are moved.