4.8is With Hissing Sound

[vlizzardv]

if it lasts only less than a minute, could it be the secondary air pump?

[deanblue9]

I dont think its he secondary pump because the hissing sounds is coming the area much higher in the engine bay; more like from the sparke plugs area.

[deanblue9]

MB Fahre, do you have the pic of the location you have mentioned? Thank you

[MB_Fahrer]

Originally Posted by deanblue9

MB Fahre, do you have the pic of the location you have mentioned? Thank you

I do not have a picture on hand, but I'll try to explain it's location in laymen's terms. If you're still lost, I'll snap a picture for you later today (provided I can remember to do so )

The hose in question runs along the wiring loom atop the drivers side head (underneath the plastic engine cover); then runs by the CCV/PCV hose (runs from drivers side head area down the front of the engine towards the passenger side block--roughly); then connects to the pastic pipe joining the throttle body to MAF (the pipe is around 8 inch long and 3 inch wide. On that plastic pipe is a small nipple to which the hose connects.

Edit: this may be of slight help for the moment. Step #18 shows the tube that rotted out on mine. http://www.horsepowerfreaks.com/imag...-10682900-.pdf

[deanblue9]

Thank you everyone for the help and inputs. I spent about three hours today tracking down the source of this annoying HISSING sound. Finally, I was able to locate the cause of the issue. I don't know what is the part or part number but it looks like a diaphragm and it was torned and ripped. If anyone knows the part number to this item I would greatly appreciated. Attached is the picture of the item/unit that need to be replaced. I hope this will help other board members in the future.

[deanblue9]

This part is under a black round plastic cover much like a headlights covers.

[MB_Fahrer]

#13 on this page is what you need. Buy two of them, as there is one on each valve cover. When you put the new ones on, be sure to seat them all the way.

http://www.realoem.com/bmw/showparts...58&hg=11&fg=15

Here is a link to purchase: http://www.rmeuropean.com/Part-Numbe..._94E6B777.aspx

[Gurjit]

make sure when u install, you hear a distictive click for all 6 of the clips

[iPolo]

first time posting hello everyone

so I had been having this same issue with my 05 for about a month now and I ended up figuring out that the cause of hissing sound was my beltdrive (pump/alt.) which was in fact a new belt but for some reason decided to dry out (defect im guessing). The hissing would start only on cold startups and by the time the engine would warm up it was gone. As soon as I speculated that the sound was coming from my beltdrive, I sprayed soapwater on the belt while the car was running and the hissing would stop. I changed the belt and its gone (for now)

[Gurjit]

Brake fluid works well to moisturize/ quite the belt