bteague

I recently replaced my VVT solenoids on the driver side of my 2011 R350. Easy breezy other than a bit of a mess because I had to remove the oil cooler cover and power steering reservoir to access some of the screws. Code was cleared and everything was fine except now I have a loud buzzing sound coming from the other side of the engine compartment on start-up and intermittently while driving.

I thought maybe it was my aux water pump so I replaced it. It's not the aux water pump because the buzz still happens when the aux water pump is disconnected from power.

On startup the noise runs for 2-3 minutes and then turns off - the buzz, not the engine.

It sounds like it's coming from near my passenger side headlamp. It's loud. It almost sounds like there is a hard piece of debris stuck in a fan although this buzz is not coming from my radiator fan and it is not that aux water pump. It does not sound like an electrical hum.

The sound is audible inside the car although it does not sound like it's coming from the dash or even near it. Standing in front of the car with the hood up it sounds like it's coming from something proximal to the headlamp and aux water pump.

What else is back there? What in the word could it be?

FWIW - it's not road noise. This noise happens even while sitting still.

Update: I got a mechanics stethoscope and I think it's this (see pic). Any ideas what this is?

bteague

For anyone who is interested, this is the air suspension solenoid valve. About 20k miles ago I replaced the air suspension with traditional struts and springs. Easy fix is to simply remove the air suspension relay. Noise is gone. Now I just wish I could figure out how to bypass the whole thing so I don't see the air suspension malfunction in the dash.

BlackML550

The system is still looking for inputs from the airmatic system. You'll have to have the ecu reprogrammed to switch it off. That's the part everyone forgets to mention when they suggest retrofitting coil springs for the airmatic.