Zo6Sel

So I have an 03 z06 with 50k miles and lately when I'm driving and it gets warm it starts making a high pitched squealing or whistling noise. Sounds like a pulley may be bad so I went ahead and switched all my idler and tensioner pulleys which were pretty rough but did not solve the problem. The noise isn't constant either, I doesn't squeal While accelerating or idling but only when slowing down or coasting, the brakes also have no effect on the noise. Seems as though the hotter the car gets the louder the noise is. With it only happening upon deceleration it's being very difficult to pinpoint this dang noise and it's driving me insane to the point where I'm embarrassed to drive my car. If anyone has any ideas about what this could be or other things to check I'd REALLY appreciate the info. Thanks guys!

TOPCATHR

I had the same problem. It was the harmonic balancer see if it wobbles
very common problem............

dadaroo

Can you get it do it in the driveway by increasing and decreasing the rpms? If so, get an auto stethoscope and locate the noise. They are inexpensive and a good tool to have.

Just be careful around the rotating machinery. Best done BEFORE you start the beer drinking.

Zo6Sel

I replaced the balancer with a fluidamper less than 5k miles ago... I will give that stethoscope a try but so far I haven't been able to get it to make the noise at all other than while moving. Seems like only when there's drag on the engine...

Bill Curlee

An auto stethoscope is always a great tool. You can try spraying a little water on your belts. If its a belt, the noise will significantly change of go away (until the belt dries)

Try removing and plugging each vacuum port on the manfold one hose at a time. Sometimes the intake manifold can make that noise.

Ive see the PCV hose /fitting rot and split open and that makes some weird noises. Look on the passengers side of the manifold near the TB

When decelerating, you have max manifold vacuum. I would be looking closely at any and all vacuum lines, TB bolts tight, manifold bolts tight,, ect...

Zo6Sel

Headed to pick up one now but I'm also inclined to think its a leak somewhere as well. Have a brand new fast 202 intake on it now and a nitrous plate. It's insane how loud the noise gets sometimes though...

Rj-lo

Mine does that sometimes too but its the opposite. The squeal/whistle happens on hard acceleration starting about 4000 rpms. Steady accelerating it doesnt happen...

:thread jack!

NITRO UK

Hi
Have you done any work on breather, pcv , catch can, work recently.

Does sound like a vac leak like Bill said.

Zo6Sel

Yep put a catch can on when the new manifold went on...

dadaroo

You say it makes the noise when decelerating. Does it do this when you DON'T use the brakes to decelerate? Just wondering if it might involve the power brake booster.

NITRO UK

Hi
I`m sure you have connected the hoses correctly , but cant hurt to check they are in the right places.

Maybe remove anything going to the manifold and take it for a run.

I had a ear splitting scream , turns out I had a hose wrong side of the throttle plate , which then sucked all the air out of the sump .

This resulted in air being sucked through the rear crank seal , and hence the noise .

Think yours may be more like a manifold leak though.

Just a thought.

cudamax

Man for over 30yrs people would come in with all kinds of weido noises and stories that made them sound nuts. In this day and age, come on man pull ur cell phone out. You said its real loud at times. Give us a video. It could be anything. So just saying a video would sure help and would be like a lot easier solving ur problem

Zo6Sel

well it makes the noise when I am on the brakes too, the brakes have no effect on the noise...

I'll try to get a video today, good thinking!

Zo6Sel

So I used my handy dandy stethoscope and when I touch the nitrous plate I hear a whistle but I'm not sure if it's from the aluminum it's made of or what. All seals seem to be ok and the bolts are tight. Everything else sounded alright. My intake bolts on the front half weren't as tight as the rear half either... It was hard to get a video because of wind noise and it was kinda quiet but I managed to get a clip if the noise bouncing off a short wall downtown... Don't know how to attach my video...



This is a pic of how my catch can is set up.

cudamax

Download/send it to Youtube then after that paste/link it here

Bill Curlee

Spray some carb cleaner out of the red spray tube around the area where the noise is coming from and see if the IDLE changes at all when you apply the solvent. If it does,, that area is leaking. You can also spray water on the area and if it gets sucked in, its leaking.

Bill

Zo6Sel

Bill Curlee

Video says its private...

Zo6Sel

Sorry about that... And
It's kinda hard to hear... It's a very faint whistle. Sounds so much louder in person

cudamax

Sounds like to me blasting the sound, that maybe its ur alt whining while its putting out
Try buzzing it up to 2000 rpm in park and try the blower on high and a/c on then turn the brights on and see if its doing it
and spray some WD-40 on ur serp belt see if it makes it better or worse and then spray some brake clean on it and put something over the front fenders See if u can get it to do it or not do it anymore
And it kinda sounds like ur running the engine with the throttle body plenum off Maybe it's loose or the air filter box is loose or coming loose
Does it do while on the throttle or on decel? or it don't matter?