Hey everyone,
I have had a fairly high pitched humming noise from my 99 xjs engine for a while. I thought i found the issue with the ac compressor but the noise is still there after replacement. Today the noise sounds worse. I checked all the fluids and they are all good except the brake fluid. I am in the process of replacing brake lines. Does anyone have any ideas as to what that noise is?

Sounds like it this general area
Second thing. This might be related to the noise but in the past 2 days I've been smelling a like burning metal smell from the exhaust and engine bay. Anyone have any thoughts? This is a project jeep that I've been fixing up and it hasn't moved in about 7 months because of the brake lines. Could the noise and smell be carbon build up on the cylinders? Last thing to note is that the smell is only when the engine is running and the jeep has no ac but some components are still there. I have a compressor bypass pulley in it a new battery new radiator cap(that leaks sometimes) and currently the muffler and tailpipe are not on die to other work I have to do. A shop also said that the alternator was on its way out but it is still charging.
If you all have any clue as to what the issue/s may be

 

Does the noise pickup with rpm? Does it change at all from cold start to at running temp?

Tried spraying rotating components with wd-40 i.e serpentine belt idler pulley, alternator, power steering pump, ac bypass pulley?

 

Where's that kid with the stethoscope when we need her?

 

Take the serpentine belt off and make sure everything spins free.

 

You can also run the engine for a short time with no belt on to see if the noise goes away .

 

Thanks for the help everyone. It turned out the alternator was burning up and the noise was from the bearings starring to lock up. That would explain the smell as well.