saubouin

At around 3200 rpm (which is my crusing speed) I can hear a noise coming from the engine hatch that sounds mostly like whistling sound. Below & above that rpm the noise goes away. Just curious if it's a normal noise for a 496 MAG?

Dave M

Mine does the same thing. Usually around 2800-3000 rpms. My 454 Mag MPI did it too but it was not as noticable.

Chris288

Mine does it also....

phebus

Mine did the same thing. A whistling, whining sound that almost sounded like a belt slipping. It was the air going through the screens on the air cleaner/spark arrestor. Replaced it with a K&N filter, and the sound went away.
Harmless sound, but irritating.

saubouin

Thanks Phebus!

hillbilly24

teh sound is actually airblowing past the IAC orrifice and can be solved with a K and N filter that that flows differnently although I have seen the sound remain after installing aftermarket filters too. Merc now offersd a piece called an IAC muffler for the 496 that is just a little piece of foam that goes in the orifice and shuts the thing up. It only costs like 5 bucks and is well worth it.

saubouin

Is there a Merc PN# for this foam thingy?

Seems like a lot cheaper solution than the K&N.

phebus

Any idea on where this IAC muffler is available, or part number? My dealer has never heard of it. Also, I wonder what effect it has on air flow?

Thanks

hillbilly24

I don't have the part numer handy but can get it when I get home in a few days, It does not affect air flow at all, it goes in the IAC orrifice wich is what allows the engine to get air at idle, air is realy onyl flowing through that passage at idle, as soon as you crack the throttle the Air flowing through that passage has no affect on anything.

GatorDave

I want one to! That whistling nosie drive's me nuts.