We just bought this 2001 S80 T6 after selling our other S80 2.9. I have found a couple "noises" on this car that we never experienced in the other one....and would like some input.

First of all, when the key is off and the car is just sitting.....there is a faint "humming" noise you can notice from the passenger compartment that sounds like it is coming out of the console in the area where it starts to go under the dash.

Secondly, when applying the brakes at a low speed (say..25 mph) you can hear a sound that almost resembles a "hiss" until the car comes to a stop. It is pretty faint, not a really loud noise, but I guess I am wondering if it could be some sort of a vacuum line or something.....????? It is not brake pads...not that kind of a sound at all.

 

1. That should be the in cabin temp sensor.
2. Maybe the brake booster is starting to leak.

 

Hmmmm....OK...can you enlighten me a bit as to how to check both of those? Thanks!!

 

1. For some reason that seems normal I hear it on a bunch of cars all the time.

2. The brake booster you can just hear the vacuum leak when you hit the brakes and when you let off it stops. Or the opposite you can hear it while driving and when you hit the brakes it stops.

 

OK, well is there a way to repair the vacuum leak in the booster without changing the entire brake booster out?

 

Nope there is not. Sorry

 

Hmmmm....wellllllll...ok! Would you go ahead and change it out now (due to safety), or wait until it gets worse? It is, as of right now, not seeming to affect the braking of the car, but I don't want to wait if there is a safety issue.

Thanks for all your help, by the way!!!

 

Your welcome.
I would wait till it gets a little worse.

 

OK will do---and thanks again!!