2002 Mercedes Benz ML500 Repair Question
Mileage: 137,000 miles.
What is noise coming from vents?
Asked by Comptech61Answer
does it make the noise with key on, engine off??
possible vacuum leak
Roy
I am not sure. Didn't try it. Will check today. If it happens with engine off/key on is that the vacuum leak or the other way around?
Thanks for the response
Alan
vacuum leak if the noise is gone
Roy
And if the noise is still there? Could it be blend door as was suggested or is there anther possibility?
Again thanks
Alan
possible but lets start somewhere and not guess
The noise only happens with engine running. It sounds like it is only on drivers side
And coming from under the dash, not from the vents
You have a vacuum leak somewhere and need to locate the source.
Noise stopping when applying brakes could mean a fault with the brake booster or related components.
I have driven the truck and the brakes seem fine. no problems stopping nor spongy. Could it still be the break boster or what other possibilities can it be? Sounds like it could be expensive to fix? or can i be lucky and have a bad or unconnected vacuum line?
It is possible to be a vacuum leakage somewhere but without further probing, you can't be sure.
If it is a brake vacuum, it won't become spongy, instead more pedal effort is needed and repeated pumping of brake pedal would result in a stiffer pedal.
When you try to start vhicle after starting, before you tirn ignition on, test if the brake pedal is soft or stiff.