high pitched noise - Posting new thread due to other being moderated

[coRoveRhd]

https://soundcloud.com/long-dust5967%2Flr4-wailing-sound

Anyone have any ideas as to what the sound could be? It started after doing a fuel injector replacement. Nothing else was disturbed. It's not PCV or anything on the serpentine belts.

 

[Jimmy Brooks]

https://soundcloud.com/long-dust5967%2Flr4-wailing-sound

Anyone have any ideas as to what the sound could be? It started after doing a fuel injector replacement. Nothing else was disturbed. It's not PCV or anything on the serpentine belts.

This is the exact sound my LR4 made when the PCV went bad. I’ll drop a YouTube video of it. Go plug the little pinhole on your PCV valve and see if the car starts freaking out and running weirdly and making a whining noise.

 

[coRoveRhd]

Alright, seems PCV is concesus, thanks all. Ordered new PCV and a new evap purge valve, cause it threw a code on that.

 

[powershift]

It sounds like there is a hole in a diaphragm and air is pushing out of it. How many miles on it? I haven't done my PCV's yet at 119k mi.. Not sure if I need them replaced.

 

[Jimmy Brooks]

Here’s what mine sounded like.

 

[coRoveRhd]

Yep I agree, sounds like PCV. Problem is, I replaced the PCV valves. I ran some tests and sealed the PCV's completely with duct tape, ran the engine only for a few seconds, strong suction on oil filler cap, and it was louder and ran very poorly. Then, put the orange rubber pieces on without springs or the black plastic caps. No sounds, engine idled great, no suction on oil filler cap. So could the PCV's be too tight?

 

[Jimmy Brooks]

Yep I agree, sounds like PCV. Problem is, I replaced the PCV valves. I ran some tests and sealed the PCV's completely with duct tape, ran the engine only for a few seconds, strong suction on oil filler cap, and it was louder and ran very poorly. Then, put the orange rubber pieces on without springs or the black plastic caps. No sounds, engine idled great, no suction on oil filler cap. So could the PCV's be too tight?

There should be vacuum through the oil cap when you remove the cap while the engine is running. I would replace the whole assembly.

 

[jlglr4]

Could be the PCV even if not torn. Mine was making noises, so I replaced it and it was better for a while, but still does it sometimes. I’ve also read that a supecharger bypass valve can make this noise, or really just any passageway through which air is flowing to fill the vacuum in the intake when the engine is shut off. I wonder if the purge valve is to blame if you have a code there.

 

[Jimmy Brooks]

I have the 5.0L. When I replaced mine they looked perfectly fine but the noise stopped when I replaced them. Wouldn’t know anything about the bypass valve for the supercharger though. I would start simple and build from there. I think PCV should be your prime suspect, I had the same thing and they fixed it and it’s probably less expensive than any of the other parts and less labor than testing the other items.

 

[joey]

Sorry your thread may have been marked as spam by the software not the mods. I was out enjoying a well deserved vacation so didn't check the forum for a bit. I just approved several posts.