BMW: 325iC, engine whine, gasket glue, timing belt tensioner

Question
Hey Josh,
Thanks for all the great advise.

Today de-tentioned T.Belt but it was not the problem

So, used a piece of vacum hose and found a leak between thermostat housing and head, that little gasket it's cracked in 3 pieces
(see enclosed pic), repaired it with some gasket glue and wistle went away for a little while,
so picked a replacement and will install it tomorrow., that should fix it.

If not it, then injector # 1 "O Ring" it's all dryed up.

http://www.freakyfranky.net/bmwstuff/gasket.JPG

-------------------------
Followup To
Question -
my spare 2/87 325iC has been sitting around for about 8 months, it has a loud engine whine, louder when at idle, it almost disappears at 3,500 rpm's.

today I did timing belt, tensioner, tensioner spring and water pump, yet whining still there.

did noticed some rubbing marks on lower T/Belt cover, so removed it and gave it another go.
still made the nasty noise.

looked carefully at distributor and rotor, no markings there, nor on any of the pulleys, even ran it without alt/wp, p/s, a/c belts.

what could it be ?
a clogged passage ?

thanks
Frank

Answer -
Frank,
 Very nice work so far.  I was thinking Alternator whine, but you said your ran the car without accessories.  

 That is unusual, I have never had an issue with this.

 Does it sound mechanical or like a vacuum leak?  I would check over all the hoses to make sure there are no leaks, as this could be a source.

 I had a 325e that made a humming noise, and I narrowed it down to the air-filter box.  I've owned several of these cars, all had the same air box, while this one is he only one that made a humming noise.  
 
 Have you located what area the noise is coming from?  it could be something on the rear of the engine, at the flywheel causing problems.

 Try to narrow it down and go from there.  But you are right, It "could" be a clogged oil gallery, or water passage.  

 Let me know what you find out.
 Thanks
 Josh

Answer
Frank,
 Good for you, glad to hear you've located the noise.  did you have coolant leaking from this gasket?  That's extremely odd to have a crack in the thermostat housing gasket, and no water coming out.  
 Injector o-rings go bad, you can test to see which one it is by spraying a light mist of starting fluid around the injectors.  If they have a vacuum leak, they will suck in the starting fluid, and you will hear the engine idle up for a second.  it's a good way to test, just dont over do it, you dont want a fire.

 Good luck
 Josh