JNorris

iTrader: (4)

Over the last few weeks I have I have had some engine noise and it seems to be getting worse. After listening around with a stethoscope I have isolated the noise to the front part of the engine above and behind the crank pulley. The noise come and goes.
The link below is to a sound file (1.3mb). The engine is cold. This is the first minute of runtime. The mic is about 2 feet below the front of the engine. As the engine warms the sound pitch changes but it is still there.

Engine sound

What do you think is making this sound?

Thanks

John

<small>[ April 28, 2002, 08:29 PM: Message edited by: JNorris ]</small>

unit213

No idea what this noise is. I have heard this coming from my engine as well. It only happens when it's cold, like you said. Once it warmed up, I'd rev it up a bit and it would go away. I was worried at first, but now I just chalk it up to her being cold blooded! I shiver in the cold too...

JNorris

iTrader: (4)

Well, I think that the noise is coming from a bad (noisy, pressure is fine according to the dash gauge) oil pump or timing chain/gear problem. As much as the car has been driven if the problem was crankshaft related it should have broken by now.
Are my ideas sound?

RacerX

I have a sound similar from under my car too. I noticed it after getting a really bad tank of gas from Exxon at Bay Area Blvd and FM528. My engine started pinging really bad so I got gas somewhere else. Pinging went away but now the noise has surfaced. Hope I didn't loose a rod bearing. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> My oil pressure has not changed as of yet.

<small>[ April 28, 2002, 09:16 PM: Message edited by: RacerX ]</small>

2000 Camaro SS

I don't know about the high pitch wine but am I the only one that hears that knock? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

JNorris

iTrader: (4)

Oh yes I hear it every day! <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> The knock/tap is the noise I am talking about. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

John

<small>[ April 28, 2002, 09:35 PM: Message edited by: JNorris ]</small>

RacerX

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JNorris:
<strong>Oh yes I hear it every day! <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> The knock/tap is the noise I am talking about. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

The whine is the AIR pump.

John</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Let me know what you find. I would be interested in seeing what mine is as well.

Plan B

Piston Slap!

RacerX

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Plan B:
<strong>Piston Slap!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So is this common? Are the pistons really too small for the bore? What kinda wear problem is this? <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

Toxic Texan

Are you sure it is not noisy injectors?

zombiedude

iTrader: (1)

That didn't sound like an injector to me. Sounded bottom end related to me. I've got 'the slap thing' happenen but it's not that loud. Just my .02

02BlackWS6

John,

I get it to. My '99 SS had it also. Now i have a 2002 WS6. My noise seems to come from the front of the motor, but around or behind the water pump. But i still get the piston slap noise in the mornings. Hope it's nothing serious.

Den

Stangeater

Bad case of piston slap....

R U A LS1

cant download the clip because im at school on their computers. BUT IS THE NOISE ALMOST LIKE IT SOUND LIKE DETONATION. Weird because i was going to post the same darn question later today.
when- motor cold
sound- tat tat tat like a fingernail on a table
and it goes away when its hot.

JNorris

iTrader: (4)

Thanks for the replies guys. Sorry I have not responded sooner but was out of town for the past few days at a location that did not have any phone lines.

I was thinking piston slap but the sound is so loud behind the timing chain cover/water pump I just don’t think it completely caused but piston slap.

I was also thinking injectors but I have unplugged one injector at a time with no reduction in noise. However the noise is timed with injector firing.

Can a bad oil pump or timing chain/gear make this type of sound?

Thanks

John

PewterZ

John...did you first hear this noise when you put the MAC headers on your car? I have a 99 and just put the MACs on mine and I hear this noise everyday now..I went to a local shop hear in Dallas and they "thought" it was the EGR flutter valve and piston slap...

Bub

My 98 Z has sounded like that every morning since I bought it, noise usually goes away after a minute or so, it gets really loud after about 2000rpm, dealer said it was piston slap.

Swills00Z

iTrader: (1)

"Cold knock?"

Go FasTA

Do you have a pulley on the car? I had a problem with an ASP pulley that wasn't properly balanced. The outer rim, which "floats" on a rubber pad, was moving around when we watched the pulley. The sound was very similar to what you're hearing. Watch the pulley for any odd movement. I switched back to stock and that solved the problem. Then I bought a new ASP and it was fine.

JNorris

iTrader: (4)

PewterZ- After the MAC headers I could hear more engine noises but I do not think I heard this sound. I might try removing the EGR and see if I still hear it.

Unfortunately the noise does not go away after the car is warmed up, just the tone/pitch changes.

Go FasTA- Yes I do have a MTI (ASP?) pulley on the car. I removed the drive belts and cranked the car and the noise was still there but was not as bad. I will try the stock pulley.

Thanks

John