W211 270 Strange Zizzing noise

[lieutenant gruber]

I think this is related to a problem I had a while ago but couldn't get to the bottom of.

I am convinced there is an escape of air or exhaust gasses from somewhere around the engine bay. From inside the car I can hear a slight zizzing note that is engine speed related: it's most audible at low town speeds. I can also hear what sounds like a typical exhaust "blow" from somewhere at the front end. From inside the car this just sounds like the engine is slightly noisier than it should be: with the door open it is more obvious.

ATS and then my indie had the car for a couple of days before Christmas but couldn't find any exhaust leaks at all but I know there is one somewhere.

Any ideas of where this zizzing and blowing noise could be coming from will be very much appreciated. It will give me something to ponder over and look for when I finally get the car in my workshop. Thanks in advanced.

 

[Taffy7hfa]

Hi, check the plastic air intake pipe that connects onto the turbo, they are prone to splitting and won't necessarily trigger a fault code, the exhaust clamp on the cat can also fail, although from your description it sounds like an intake leak.

 

[lieutenant gruber]

Cheers Taffy7hfa,

Presumably this is an easy find?