EXTREME LOUD very very hi pitch scream from somewhere in engine, HELP.
10-01-2012, 12:02 PM
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EXTREME LOUD very very hi pitch scream from somewhere in engine, HELP. Ive had this 99 Z28 for only few weeks, and the car now has a ridiculously loud SCREAMING whine from somewhere in the engine compartment. IT ONLY HAPPENS AT IDLE. once you rev up the car past 1200 or so rpm the whine goes away. i did try spraying water on all the accessory drive belts to see if it went away but no. plus, once the car is started, it doesnt do it. but after the car warms up, and is driven for a while, the minute i put the clutch in and the rpms stablize at idle, this high pitched whine starts, almost like a supercharger whine but 100 times as loud and much much higher pitch. i have no idea what to check. I did recently have the IAC motor out trying to diagnose a check engine light, but the IAC was fine, turned out bad pcv to intake manifold hose. (had to use electrical tape and peice of 3/8 hose to fix, gonna do PCV mod soon, i just dont have the part numbers needed for the mod)
any idea on what the screaming could be coming from, i know it has to be a vacuum leak but the pitch is so high i cant tell where the noise is exactly
THANKS FOR ANY AND ALL IDEAS I WILL CHECK ANYTHING!!!
any idea on what the screaming could be coming from, i know it has to be a vacuum leak but the pitch is so high i cant tell where the noise is exactly
THANKS FOR ANY AND ALL IDEAS I WILL CHECK ANYTHING!!!
10-01-2012, 05:29 PM
#2
All stock?
I removed some of my AIR, EGR, etc and the rubber plugs I used to cover some of the ports dry rotted and make a squeeling noise. Just gotta search for it! Grab a plate or something that will block noise and move it around your engine bay until you notice it get a little quieter, then you'll know it's somewhere on the other side of the plate.
I removed some of my AIR, EGR, etc and the rubber plugs I used to cover some of the ports dry rotted and make a squeeling noise. Just gotta search for it! Grab a plate or something that will block noise and move it around your engine bay until you notice it get a little quieter, then you'll know it's somewhere on the other side of the plate.
10-01-2012, 08:10 PM
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damn good idea. hard to pinpoint the noise since its so high pitced. the tone doesnt change either. car has one engine mod the slp lid and what looks like the flopac kit. im a ls1 newb kinda so i dont kniw what the noises are ie that whine then click while the engine warms up lol
10-02-2012, 10:22 AM
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it has seemed to stop and go. i know there is a pcv mod link somewhere that shows a way as well as the parts needed to replace the pcv valve location to one where the valve is upright so as not to allow oil into the pcv system.
it uses a pcv valve with a 90 degree end, which stands the pcv vavle upright, rather than inline with the vacuum inlet at the bottom of the intake manifold vacuum port. I had to use electrical tape to seal the rotted hoses from all the oil in the pcv line that runs around the back of the engine (99 ls1)
i dont know if anyone knows of this mod or has a link to it? my intake manifold has a lot of oil build up in it. when i pulled the old pcv valve, the hose inside was almost completley blocked by oil and crud from the valve covers. stupid design as the pcv valve on my motor is located BELOW the rocker cover flange.
the other issue of course is the screaming vacuum leak sound, which i think has stopped, but starts up no and again.
i pretty much i think have to replace the entire pcv assembly hose which is on the top of the motor, starts on the drivers side rear rocker cover, runs around the back, taps off the rear pass. side rocker cover, then runs forward from the back to the pcv valve near the intake manifold. any clue where to find this hose assembly?
it uses a pcv valve with a 90 degree end, which stands the pcv vavle upright, rather than inline with the vacuum inlet at the bottom of the intake manifold vacuum port. I had to use electrical tape to seal the rotted hoses from all the oil in the pcv line that runs around the back of the engine (99 ls1)
i dont know if anyone knows of this mod or has a link to it? my intake manifold has a lot of oil build up in it. when i pulled the old pcv valve, the hose inside was almost completley blocked by oil and crud from the valve covers. stupid design as the pcv valve on my motor is located BELOW the rocker cover flange.
the other issue of course is the screaming vacuum leak sound, which i think has stopped, but starts up no and again.
i pretty much i think have to replace the entire pcv assembly hose which is on the top of the motor, starts on the drivers side rear rocker cover, runs around the back, taps off the rear pass. side rocker cover, then runs forward from the back to the pcv valve near the intake manifold. any clue where to find this hose assembly?
