Hissing Sound From Back of M60

[Fetch]

Noticed this today,
With the hood open & engine running after returning from a ride I heard a hissing noise coming from the back of the engine. Also seemed to be more on the passenger side.
I could change the hissing (lessen?) by opening the throttle a little bit, and if I flicked the throttle, the area the hissing was coming from would make a hic-up type sound.

I searched & didn't really find anything that matched.

Car has been running just same as always (knock on plastic wood)

Is this the infamous M60 intake gaskets leaking/sucking air in?

[632 Regal]

did you get any CEL codes yet?


Is this the infamous M60 intake gaskets leaking/sucking air in?

[Fetch]

did you get any CEL codes yet?

Nope nothin' yet,
maybe as it gets colder out I'll be so lucky

[BlueM60]

Ive noticed this sound many times on this engine. I would call it normal, if there were a massive vacuum leak like that, your car would be running like crap. Alot of times in the CC vent valve has blown out (the one at the back on the intake) it will make a honking type noise and youll be sucking oil into the intake causing white smoke at start-up.

-Ben

[winfred]

spray carb cleaner all around the intake and see if the idle changes while the engine is cold and again when its hot if you get nothing cold, the honking sound is not a dead giveaway, out of probably a dozen blown plates i've only seen one honk

[Rigmaster]

Sounds like it could be the infamous throttle plate diaphragm leaking (#3 in this diagram):


http://realoem.com/bmw/showparts.do?model=HE23&mospid=47406&btnr=11_1498&hg=11&fg=40


It's evidently a fairly common failure. I've seen info online about it and how to fix it.


Bret.

[BillionPa]

BAV auto has a kit that contains the gasket and parts needed to replace the entire thing for something like $65

[Fetch]

Thanks everybody, going to check it out further

[Fetch]

OK, I checked it out, I've got to leave soon, so I will post pictures later today, but:

I took the plastic beauty cover off the engine and even before starting the engine was able to guess where the hissing sound was coming from just by looking!!!

The vacuum hose connected to the part 'inbetween' parts #12 and #2 was cracked at the end, sure enough this was causing the noise. I clipped off the bad part of the hose & reconnected it (hose should be replaced if I do any work with the intake (gaskets) though).

http://www.realoem.com/bmw/showparts.do?model=HE13&mospid=47406&btnr=13_0385&hg=13&fg=15

Is this 'unnamed' part, part of the pressure regulator (#4)?


Also, there was a two pronged wiring harness (not plugged in) tucked away under the fuel rail I hadn't noticed before....I'll post pics, but I couldn't find anywhere this thing is supposed to be connected...donno what it's for.

[winfred]

yea thats the regulator, don't worry about the extra plug it's for something you don't have

[Fetch]

Ahhh, here's the pics for old times sake, for someone's future reference maybe:

Here's the hisser (hose removed for dramatic effect):
http://img141.imageshack.us/img141/5507/pict2618smallvu9.jpg

And, here's the unused connector:
http://img243.imageshack.us/img243/332/pict2617smallmy9.jpg