My 99 ss developed this chirp last fall, thinking it was just a pulley I didn't worry about it and put it away for the winter, now that spring is approaching I went to find out what pulley and found it isnt a pulley at all, now its driving me crazy because I cant find the noise! The noise appears to be coming from the passenger side head/intake area, with both belts off it is still there, I pulled the rocker arms on that side and all seem fine, I checked the push rods and all are straight, I cant push any of the lifters down with a piece of wood by hand, noise is still there with oil cap off, checked all header bolts, put a stethoscope on all rocker bolts and didnt hear a difference, I cant pinpoint it to anywhere on the head/block/intake/injectors etc.. I dont want to pull the head unless I can narrow it down a little more to lifters. Squezzing the upper radiator hose makes a noise but I dont see how that would transfer to the noise Im hunting without the belt on, I have a couple of videos Ill post, any help is appreciated, thanks!

Its a 99 ss m6 with an lq9 h/c/i car

https://youtu.be/Ah5mRZ7-B3o
https://youtu.be/ejVVBklxcUE
https://youtu.be/c51J4bo5YCo

 

Sure it isn't the common lifter tick?

 

All kinds of valve train parts can make strange noises.

I had a BBC once that as I turned the crank by hand it would go rrrrreeeeeek.... rrrrrrrreeeeeeeeeeekkk... turned out to be a valve spring rubbing on its damper. Turned into a sort of a "tick" when the motor was running but was ... something else ... when turned slowly.

I don't see in your post how you "found" it's not a belt/pulley/accessory related noise. Did you remove the belt and start the car?

 

It doesn't really sound like lifter to me, lifters are usually a little more consistent, that noise kinda changes here and there, and it's really weird that squeezing the radiator hose makes a similar sound. I would look at the thermostat for that one, it's about the only thing I can picture in the cooling system that would get funky and has little parts that could come loose and make noises. Although i've never seen anything like that. Did you spin the water pump with the belt off and look for weirdness there? Pull on the pulley and see if there's any movement or noise?

The noise to me almost sounds like something rubbing or possibly even an exhaust leak.

Here's how I find exhaust leaks at the shop. Take your stethoscope and pull the plastic end off to where you just have the rubber tube, put a piece of brake line in it and bend the end of the brake line a little to get it under the exhaust manifold then run the brake line all around all the exhaust gaskets and collectors and see if anything pops up. This also works for vacuum leaks and pinpointing them btw.

If it's not that, maybe try sticking a jack under the engine while it's running, just to put the exhaust and the mounts and everything in a different position and see if the noise changes. If it does then look for something rubbing or something loose like a bracket or motor mount bolts.

Don't forget to stethoscope the k member, motor mounts, manifolds etc to see if anything pops up there.

I wish it were an auto i'd tell you to put it in gear (forward and reverse) and see if anything changes with some load on it. You can try it anyway, if you get it to stop while loading the engine in forward or reverse that will also help to tell you if it's something rubbing.


I watched the vids a few times, half the time I think it's not a lifter and half the time I think it is..

 

I did run it with the belts off and the noise is still there.

 

PooterSS, thanks! I will definitely try that stethoscope trick and jacking the engine, I never even thought of that. I can try loading the engine to, I did shake down the wp pulley with the belt off, I was so convinced it was in the head I started over looking stuff I guess. Ive never really heard a bad lifter roller in person so im not quite sure what it sounds like but that's what I was leaning torwards. Thanks again for the advice.

 

Anytime man, I've been a tech for near 20 years so I've had to improvise a lot of things chasing noises. Good luck and I'll check back.

 

 

I tried that already, no difference.

 

post a video of the sound

 

Most likely a bad lifter, the roller starts to fail and it will chirp as it run over the ramp of the cam. You can pull each rocker 1 at a time until you find it. Also check the rocker trunion bearings off the engine.

 

I put 3 youtube links at the end of the first post, not sure if there is a better way to link a vid.

 

I never started it with any of the lifters off, Ill try that this weekend as well, Im leaning torwards a lifter myself but thought I would be able to pick it up with a stethoscope on the rocker bolt, thanks for the help/reply.

 

use the insert video link button on the post and then it will hotlink.

 

You redid your harness and caused a chirp, and pulling the oil cap fixed the noise? Cause by redoing the harness???

 

LOL good point.

I don't want to take away from OP thread so I'll try to be brief. i pulled intake and all of my harness out to rewire it (remove t56 wiring, move grounds to front of head for future, speedo via ABS sensor for my th400)

when i put the intake back on, got sloppy with the vacuum connections. if you f'up vacuum connections you will get that chirping sound. that's why i was asking if his situation similar. and now you know how i got there.

 

lol I was so confused!

What vacuum connection caused the noise?

 

my passenger valve cover to new throttle body. the new (used) throttle body had the port blocked (think he was using a catch can). Anyway, doing this late at night after family asleep and me tired I didn't process at the time and plugged my fresh air passenger valve cover into the INTAKE So it started fine, but when it got chirping, i stopped and did some research and then found that is one way to make it. so a 2 min fix.

 

I had it running with the right v/c off and the chirp was still there, Im going to try a couole of the suggestions mentioned above and if its still there im going to most likely pull the heads this weekend, it has head studs so Im not looking forward to it, I also dont want to keep running it hunting for the noise because Id like to salvage the cam if it isn't junk already.

 

Merim123 thank you! I did not realize that.