Help! Exhaust Leak-Air Pump noise

[savorino]

I have a 2001 Aurora 3.5 w/ 37K. there is a noise that comes on as I accelerate, sounds like an exhaust leak but I suspect the air pump system. I removed the cover in the drivers wheel well and inspected, could not get it to make noise in the drive.Is there anything at the back exhaust manifold that leaks?
Any help would be appreciated.
No check engine light.
Sav

[Marc]

My guess, according to your description: the rear exhaust manifold gasket could be leaking. Also check the connection between the rear exhaust manifold & the exhaust pipe. There's a gasket there. Also watch out for loose bolts at the places that I mentioned.

[savorino]

I now do not believe it to be exhaust related. The sound does not increase or decrease with engine speed. While driving I slipped the car in neutral, the RPM's decreased with no change in sound, REV'ed motor and no increase in sound. I still think its the emission air pump running continuous at speed-or bleeding off at speed. But now I may have to consider wheel bearings and the like.

[New442]

FYI- My 01 4.0 has gone through 3 wheel bearings since I've had it, but it never made any noise that you describe.

[savorino]

I checked the brakes and one of the linings had separated from the backing plate. thought it was that but still made the noise after doing the front brakes. removed and plugged the air pump at LF fender. still noise.
One person had commented that his ABS ring had come off his bearing. Makes me still suspect a Bearing despite the valued info from NEW442.
I now suspect the air pump valves at each corner of the engine. it appears that one was replaced(LH shiny RH corroded). Although the noise is speed related and not RPM related!?

[apostolakisl]

try putting the car in neutral while moving and shut off the engine. If it still makes the noise then it is probably wheel bearings.