sambam2006

Hi Guys,

I'm having an issue with my engine and was advised to post in this section as many of you have M157 knowledge, hopefully something you can help me with.

I've been having this issue were I can hear a high pitch sound, it's been here since December 2020, can't seem to source it, Mercedes says all is good but I know something is wrong.
I recently had this fault come up, went to Mercedes and paid stupid amount to fix the issue below, replaced coolant circulation pump, same error still there. I kept the old pump which apparently was working fine.

Symptoms I have on the M157:
Seems to be watery liquid under the intercooler box between intake manifold (same colour as oil but watery).
High pitched noise
Tiny drops of watery oil is found dropping from ac compressor/condenser said the Mercedes technician but told me not to worry

Car performance is not affected, it drives, no lag or power issue. No drips of oil or watery liquid under the tray.

I'm tired of this issue as I can't seem to pin point the high pitched noise or the actually issue, I 've spent over £1800 trying to diagnose with Mercedes.

Any ideas or tips so I can fault find?

kenneyd

Sorry I can't be a lot of help, but the popular "always on mod" for the pump will show the error in xentry that you have.
Did you or the previous owner do the always-on mod?

BCP

You can locate the IC pump relay and check to see if the brown wire w/blue tracer has been grounded - this will show if the aforementioned mod was performed.

sambam2006

I've never heard of this mod, anywhere where I can find more info on this?

​​​​​​​many thanks

sambam2006

Thank you I will look into this