My yr 2000 E320cdi continues to sound like a jet engine after I turn it
off. This goes on for quite a time i.e. several minutes.
It is not as loud as an rb211 jet (obviously) but has the same kind of
spectrum.
I should be more analytical but it seems to happen more after short
journeys than long journeys where the car is really warmed up. It also
starts loudest and then gets a bit quieter.
I have no idea what the noise is.
Roland Franzius - 27 Feb 2009 18:06 GMT
nihil schrieb:
> My yr 2000 E320cdi continues to sound like a jet engine after I turn it
> off. This goes on for quite a time i.e. several minutes.
Off? Is runnung after shut off?
> It is not as loud as an rb211 jet (obviously) but has the same kind of
> spectrum.
[quoted text clipped - 4 lines]
>
> I have no idea what the noise is.
Do you mean something like the turbo prop noise of a cold lose rubber
belt? Rubber contracts after warming up by slipping.

Signature
Roland Franzius
Cordy - 28 Feb 2009 06:45 GMT
nihil ha scritto:
> My yr 2000 E320cdi continues to sound like a jet engine after I turn
> it off. This goes on for quite a time i.e. several minutes.
[quoted text clipped - 7 lines]
>
> I have no idea what the noise is.
Most probably the cooling system is still on, when you switch engine
off. First, I'd check carefully the level of coolant. Not only in the
plastic bowl, but also in the radiator: sometimes the cap of the
radiator stops opening correctly.
Anonymous - 02 Mar 2009 06:16 GMT
> nihil ha scritto:
>> My yr 2000 E320cdi continues to sound like a jet engine after I turn it
[quoted text clipped - 13 lines]
> bowl, but also in the radiator: sometimes the cap of the radiator stops
> opening correctly.
When I had an E320CDI I thought the heater water circulation pump would be
running a while after the engine was switched off but it isn't. If this
noise s something similar, more continuous than from the cooling system or
AC, I believe it is one vacuum controlled flap that keeps going until vacuum
is lost. An MB workshop expert explained me where this noise comes from but
I really cannot remember the exact part any more. Totally harmless if it is
the same.
nihil - 02 Mar 2009 11:49 GMT
>> nihil ha scritto:
>>> My yr 2000 E320cdi continues to sound like a jet engine after I turn it
[quoted text clipped - 20 lines]
> I really cannot remember the exact part any more. Totally harmless if it is
> the same.
Yesterday I re-tightened the coolant expansion tank cap and set off for
a 12 mile journey (there is no radiator cap). At the end of it I turned
the engine off and there was no noise.
However, when I returned home a few house later and when it was
significantly colder, the noise continued after turning the engine off.
The noise comes from the front right hand side of the engine bay (same
side as the turbo). I don't know if this is where the heater water pump
is situated.
The difference between the two journeys was the outside temperature. Is
it possible that the catalytic water heater was activated on the colder
return journey but not on the warmer outward journey and that the noise,
as you say, is the heater water circulation pump? It stopped after about
4 minutes.
Tiger - 02 Mar 2009 16:55 GMT
Replace that coolant safety cap.
Jens - 02 Mar 2009 10:53 GMT
> My yr 2000 E320cdi continues to sound like a jet engine after I turn it
> off. This goes on for quite a time i.e. several minutes.
[quoted text clipped - 7 lines]
>
> I have no idea what the noise is.
After switching on the engine, the fuel pressure in the fuel rail
(across the fuel injectors) should normally still stay high. If either
the pressure regulator valve or a check in the pump system is not
shutting off completely, it could give such type of noise (decreasing
as pressure slowly drops).
Jens - 02 Mar 2009 10:55 GMT
> After switching on the engine....
Of course I mean off...
nihil - 05 Mar 2009 21:46 GMT
>> After switching on the engine....
>
> Of course I mean off...
It is the catalytic water heater. If I turn the switch off (under the
flap by the ashtray) the noise doesn't happen.
If it is cold even after a long journey this heater is activated. It is
supposed to turn off when the engine reaches operating temperature.
However there is a fault in either the thermostat or the temperature
sensor such that the recorded temperature is never more than about 65
degrees Centigrade. The low reading is probably causing the heater to
remain on.
Now I now I just switch it off when the engine has warmed up.
I do not know whether to spend £40 to replace the thermostat and
temperature sensor (which are all in one unit). I have heard reports
that these cdi engines run cold anyway and that the temperature sensor
under-reads.
John (Ireland) - 10 Mar 2009 23:22 GMT
I have a C270CDI and it does the same, a rumbling/rotating noise for a
few minutes after shut-down from somewhere in behind the trubo area,
and runs cool per its own temp gauge. I'll try switching off the
heater as you suggest to see if it makes any difference.
John in Ireland
> >> After switching on the engine....
>
[quoted text clipped - 16 lines]
> that these cdi engines run cold anyway and that the temperature sensor
> under-reads.
Borg Queen - 17 Mar 2009 05:46 GMT
Your mercedes is possessed by the devil, you must exorcise it.
>I have a C270CDI and it does the same, a rumbling/rotating noise for a
>few minutes after shut-down from somewhere in behind the turbo area,
[quoted text clipped - 24 lines]
>> that these cd i engines run cold anyway and that the temperature sensor
>> under-reads.
richard - 17 Mar 2009 06:08 GMT
> Your mercedes is possessed by the devil, you must exorcise it.
Sounds like it. I don't understand it neither why heater is
supposed to turn on and off based on engine temperature. It
ought to be controllable by human, auto on and auto off.