Need help diagnosing chatter noise

ACSPONY

Dirt-Old 20+Year Member
Oct 10, 2004
711
2
19
Ohio
A little background:
I had an intermittent check oil light for a while due to leaky valve covers, which I band-aided at school for a few months since I had nowhere to work on the car. I'm home now and within the last few days heard a ticking noise on acceleration, it didn't seem to get faster or louder but I heard it most around 2000rpm. The next day I thought I heard a chatter that seemed to go from the driver's to the passenger's side of the car, but it was intermittent.

I just finished replacing the valve cover gaskets today, did an oil change, and added a can of Restore. I think I have the leak problem licked now, but when I took the car out to heat it up before finishing torquing the intake bolts, I heard the chatter again, but only on deceleration, right around 1500rpm. The idle seemed to hang for a split second there and when it dropped the chatter went away. The sound reminds me of sticking a piece of paper in a fan, and I'm convinced it's not the flip-up sunroof, or the ashtray door. I can try to get a video of the noise, but in the meantime, any ideas? Car has ~92k and mods are in sig.

Thanks.
 
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That's what I thought before I replaced the covers, and I tightened up the header bolts, but my plan was to torque them tomorrow. The Chilton's manual says 18-24 ft-lbs so I was going to do 21 and see if I got anymore noise.
 
I tightened up the headers as best I could, I could only get an open end wrench on most of the bolts, and after driving the car the sound appears to be coming from under the car. I only hear it under load, I'd call it clacking vs ticking. Everything is fine when I rev the car in neutral. I am going to try to get under there and see if anything in the driveline appears out of the norm. How can I test for play in the u-joint or at the transmission? Just see if I can move anything laterally with my hands? Thanks.
 
Sounds very similar to what my Mustang is doing. Might be a loose catalytic converter heat shield. But I guess that would be best case scenario.

not very likely in his case since he has a off road mid pipe. :p

If you can get someone to rev the car to certain RPM and see if you can hear it that way while you look around. Might be an accessory. If you hear it with the belt on and not sure where it's coming from. try taking the belt off to rule out the possibility of it being an accessory.

put the rear end on jack stands if this helps so you spin the back wheels

my alt. made a weird sound but only made it at 900-1000 rpm. any less/more it made no noise
 
No, you're right. I have an o/r x, but it's off the car right now since I didn't put it on after emissions testing :p. My thought was either a cat shield or the u-joints as well. It definitely sounds like something is loose and vibrating. I would guess loose because it's not rhythmical. I'm going to jack the car up and take a look. So, cat shielding and u-joints. How do I tell if the u-joints are bad?
 
*Update*

I let my dad drive the car yesterday and he thinks it's clutch chatter. Is there a way to tell if it's the disc or should I just go ahead and replace everything? I'm looking at the King Cobra kit.
 
The U-Joints will usually give a ringing or clicking sound when you are taking off from a dead stop or engine braking to a stop. They will also vibrate at speed. You will have to get under the car while well supported and give the drive shaft a shake and/or a twist. Any movement is no good (besides obvious slack in the transmission and diff).

A possible clutch related sound is the throw out bearing, but it will tend to make more noise when you have the clutch pressed in (ticking / clicking sound). Now if you get chatter when the clutch is engaging, it's probably just plain worn out. There are several things you might want to have repaired while you are in the area of the clutch (throw out bearing, pilot bearing, rear seal, re-surface flywheel, etc.)
 
Thanks for the reply. The pedal and shifter feel fine, I don't get any vibration through them so maybe it's something else? There's no noise in neutral or when I hold the clutch in so I think the TOB is okay, I get the sound at speed, or if I'm in gear cruising and take my foot off the gas pedal and let the engine braking slow the car.
 
As of right now I have something going on in the valve train at my # 1 piston. Haven't pulled it apart to look yet but I know that's definitely where it's coming from. At first I thought the "ticking/knocking etc..." was coming from under the car because I had the hood closed and the sound was traveling down making it sound like it was somewhere around the collector on the header. But after opening the hood I could tell it was coming from inside the valve train. If you ran the car without a sufficeint amount of oil for a while it may be the lifters...maybe I'm completely wrong...but just a thought...hope all goes well
 
It's time to buy a cheap automotive stethoscope to help locate the noise. The cost is $10-$14, check your local auto parts store or Google it to find a bargain.
 
I finally caught the noise on video, got it in neutral today as well as driving so maybe it's not in the driveline? Video descriptions tell you when in the video the sound comes in.

Video 1: YouTube - Chatter 1

Video 2: YouTube - Chatter 2

I listened to the clips several times, even tried headphones, and I could not be sure when I was actually hearing the sound, and not wind noise or lens cap, etc. Maybe you can get the car up on a rack and duplicate the noise with someone underneath (?)
 
Thanks for taking a listen. It's harder to hear in the first clip, but between 2 and 3 seconds in the 2nd clip you can listen for a machine gun noise. I agree it's hard to hear above the exhaust and the fan..
 
Thanks for taking a listen. It's harder to hear in the first clip, but between 2 and 3 seconds in the 2nd clip you can listen for a machine gun noise. I agree it's hard to hear above the exhaust and the fan..

Okay, I think I finally heard at the beginning of clip 2. Very hard to tell, but it sounds engine related to me, maybe a light metalic sound like rod bearings or maybe lifter noise. It could be so many things. I would just keep a close eye on the oil pressure and go easy on the engine. It might last forever that way, or..... maybe not. Most of these engines that have 100k plus miles on them have a few noises that give them character.

:D
 
Well I've got 92k on her and I did an oil change tonight with 10W40 to see if it's a lifter issue. If not, I'll get under there and check the shifter linkage before I take it in to a shop. Oil pressure seems okay (from the stock gauge anyway:rolleyes:) but an aftermarket oil pressure gauge is next on my to-do list.

Thanks for the reply.