Whistle noise at idle

I had this whistle at idle on my 2)4bbl. 354 Hemi. Chased it for a while. Checked ALT. doides by removing belt, no go. checked all over for vacuum leak, no go. Turns out it was PCV rubber grommet, with the cross slits in the grommet. The second I pulled out the PCV on the running engine the whistle stopped. I took a sharp pointed scribe and poked an extra hole in the grommet and the noise went away. So If you have a similar noise give this a try.




Ago

 

why are you running a grommet with a restrictor in it?? it should be open on the bottom as the valve regulates the flow .

 

Sounds like the crankcase is sealed? Should have some air flow in through oil cap.
Newer vehicles there's a hose between valve cover and air cleaner.

 

The valley pan is vented through the original style oil cap. The grommet is not restricted just baffled. the baffle was making the whistle noise.


Ago

 

Similar grommet story: I had a squeal sound on my 1980s Ford pickup, sounded like an alternator bearing.... turned out to be a rubber vacuum port cap on the carburetor, with a hole in it.

Never jump to conclusions....

 

Does the whistle go away as you give it throttle,if so you have a vacuum leak most likely at the carb to intake base

 

I had a similar issue found out the intake had a hairline crack in it where it met the head, when it got hot the whistle went away expansion of the metal when hot. took a while to track it down only happened the first 20 minutes or so the car was running.

 

Having the same problem on a 289 with a 390 Holley. Just replaced the base and spacer gaskets with no change. Does not do it cold only when it warms up and will stop whistling at random times.

 

Mine did the same thing when warm. Pull out the PCV and see if it stops.


Ago

 

More experiments.

Pulled the PCV, plugged the line. Still whistled.

Checked all the mounting studs, manifold bolts, etc. still whistled

Took of the air cleaner, revved it a couple of times. Whistle goes away for a while.

Happens after warmed up, not when cold. Still have no idea.

 

I had a sbc with a whistle that was nearly the same thing, someone put a cheap hose on the pvc & it was ****ing closed

 

When the engine is running, I usually spray throttle body cleaner around the vacuum lines, intake, and anything else that pulls air. If you have a leak the noise will go away and you might even hear a hiccup in the engine. It will help pinpoint the noise/leak. just make sure you don't have a plug wire arcing. I caught a dodge ram on fire at work that way one time. I got the fire out quick, but damn near ruined a pair of skivvies in the process.

 

I had a whistle sound that turned out to be from a carb gasket was turned upside down. The gasket was old and the under side shape of the Edelbrock carb was pressed into the gasket so being upside down it left a good air p***age for the whistle sound.

 

I did the same thing on a full size bronco with a 351 in it. Checking for an intake leak I sprayed carb cleaner and within seconds HUGE underhood fire. Luckily the extinguisher was right there and I got it put out before it did any damage to anything other than my pride.