I have a 325i 2003. The power steering reservoir is leaking ever so little, However there is an odor coming from the engine when the engine is hot. The reservior is maintaining it's fluid according to the dip-stick. The odor smells like burnt rubber and comes from the passenger side of the engine near or on the manifold. Would this happen if the fluid from the power steering reservoir was leaking on too the fan belt or the manifold itself?

If you can't find a power steering fluid reservoir under the hood in the engine compartment your G6 could have Electronic Power Steering . If you look up under the dash below the steering column you will see a electric motor mounted to the steering column !
The power steering system reduces the amount of effort needed to steer the vehicle. The system uses the powertrain control module (PCM), body control module (BCM), power steering control module (PSCM), discrete battery voltage supply circuit, steering shaft torque sensor, steering wheel position sensor, power steering motor, driver information center (DIC), and the serial data circuit to perform the system functions. The PSCM and the power steering motor are serviced as an assembly and are serviced separately from the steering column assembly. The steering shaft torque sensor and the steering wheel position sensor are not serviced separately from each other or from the steering column assembly. The steering column assembly does not include the power steering motor and module assembly.

It could be a leaking hose, and the PS fluid is dropping on the hot exhaust. Check the fluid level in the power steering reservoir. If low or dry, look for a leak.
I don't know about the rattling-better have someone look at it.

No-

It could well be a PVC valve. The PVC plumbing on e46s is not one of BMW's best designs, and it needs to be cleaned out every 100k miles if not sooner.
Not likely a rear main. I have never seen a failed rear main seal on a 6 Cyl BMW.

Are you sure it is not power steering fluid? I would be surprised if a 2003 were not leaking a little power steering fluid by now if the hoses have not already been replaced.
Another common oil leak is the hose that feeds oil to the VANOS.
If the leak is toward the rear of the engine, I would look for a valve cover gasket leak.
The service engine soon light is almost certainly unrelated to the oil leak.

YOU HAVE A RUPTURE PRESSURE LINE IF YOU HAVE NO POWER STEERING FLUID IN THE POWER STEERING RESERVOIR.LOCATE LEAK THEN BLEED POWER STEERING SYSTEM BY ADDING POWER STEERING TO RESERVOIR.DONT OVER FILL BY FULL COLD MARK ON POWER STEERING DIP STICK.ADD FLUID TO RESERVOIR WAIT A 2 MINUTES.CHECK FLUID LEVEL AGAIN.WHEN POWER STEERING FLUID LEVEL STOP DROPPING.START ENGINE LET IT RUN FOR 10 SECONDS.THEN TURN OFF ENGINE CHECK POWER STEERING FLUID ADD FLUID IF FLUID LEVEL DROPS. WHEN FLUID LEVEL STOP DROPPING.SAFELY RAISE SUPPORT VECHICLE FRONT WHEELS.START ENGINE.NOW TURN STEERING WHEEL GENTLY FROM STOP TO STOP MEANING LEFT TO RIGHT DONT HOLD IN POSITION.LET THE STOP TO STOP BE QUICK.CHECK POWER STEERING FLUID AFTER YOU HAVE TURN STEERING WHEEL ABOUT 7 STOP TO STOP.WHEN FLUID LEVEL STOP DROPPING YOU AT HOT MARK ON DIP STICK BLEEDING PROCESS COMPLETE.TURN OFF ENGINE LOWER VECHICLE BACK TO GROUND WAIT ABOUT 5 MINUTES CHECK YOUR FLUID LEVEL.IF FLUID LOOKS LIKE A TAN COLOR.YOUR POWER STEERING SYSTEM FULL OF AIR.TURN OFF VECHICLE LET VECHICLE SET A LONG WHILE TO AIR BUBBLES SETTLE DOWN LOOK FOR LEAKS AROUND POWER STEERING PUMP FRONT SEAL AND CHECK FOR LEAKS AROUND POWER STEERING LINES.

POWER STEERING FLUID GOES IN THE POWER STEERING PUMP RESERVOIR WHICH IS PART OF PUMP.POWER STEERING FLUID RESERVOIR SITS IN FRONT OF ENGINE LOOK FOR A RESERVOIR WITH A ROUND COVER THAT READ POWER STEERING FLUID ONLY.REMOVE COVER LOOK AT COVER DIP STICK POWER STEERING FLUID LEVEL SHOULD BE AT COLD MARK FOR COLD ENGINE HOT MARK ON DIP STICK WITH A HOT ENGINE.DONT OVER FILL.

Subie's power steering resivoir is mounted on top of the engine and are notorious for leaking onto the top of the engine and puddling on top of the head. Once the engine reaches normal op temp, it burns the puddle of fluid and produces the burnt oil smell and sometimes a bit of smoke coming out from under the hood. I have driven my legacy like this for thousands of miles. You can either fix/replace the reservoir, or just top off the fluid (dextron 3 or 4 ATF) and clean the pooled fluid off the top of the engine at the car wash. Hope this helps!

your power steering pump has a cap on it.you have cold mark and hot mark.when car is cold engine not running.when you remove power steering cap it should be on cold mark.if not add until you get to cold mark on cap stick..dont over fill or you blow the seal.now when engine is hot been running.turn off car check.power steering cap should read full hot.mean level is correct.when you first check power steering fluid and it was real real low.you got a leaking high pressure hose.or power steering pump seal is leaking.if all check out good.your problem could be low tire pressure.worn ball joints.and tie rod ends.rack and pinion steering gear binding.

there,s a chance that your hot-cold air trap is not working

when looking at the engine with the hood up, look to the right hand side for something that looks like this (#1 in the pic): http://www.realoem.com/bmw/showparts.do?model=ET37&mospid=47720&btnr=32_0957&hg=32&fg=20

it will be black in color, but don't confuse it with the oil filter housing. power steering reservoir will have a unique cap (#2 in the pic) that can be removed with your hand. the one that has the large nut on top is the oil filter. remove the cap and put in the correct fluid.

hope this helped.