What is this sound?
Thread Starter
Racer
Joined: Dec 1999
Posts: 442
Likes: 0
From: Dallas,TX,USA
What is this sound?
Another new sound; as far as I can tell it is either eminating from below the intake, or near the flywheel are. Beyond that, I cannot localize any further. I tried the screwdriver trick but it does not really help. Any ideas? Thanks guys.
http://home.comcast.net/~twelvemeter/DSCF0339.AVI
http://home.comcast.net/~twelvemeter/DSCF0339.AVI
Drifting
Joined: May 2006
Posts: 1,871
Likes: 0
From: Arlington Texas, originally from San Angelo, TX
Originally Posted by RunNE1
The sound is constant. It cycles faster with increased RPM.
You might try and locate an automotive stethoscope to help isolate the tapp. How is your operating temperature doing? Is it within it's normal range? I have spun a few bearings which sounded quite similar, but with that comes excessive heat.
Drifting
Joined: May 2006
Posts: 1,871
Likes: 0
From: Arlington Texas, originally from San Angelo, TX
Have you ruled out valvetrain as the culprit? Is the sound much more prominant from underneath the car as compared to above? I assume it is being as though you recorded from below.
Thread Starter
Racer
Joined: Dec 1999
Posts: 442
Likes: 0
From: Dallas,TX,USA
I have already checked for bent pushrods. I did not remove the springs, but I did not see an obvious problem with them. The operating temp is fine. There is no signs of trouble other than the noise itself. I checked the codes, and I have an O2 sensor error code, but I am sure it is not causing that sound. It does seem louder underneath the car than above it; unless you are right over the intake manifold near the firewall.
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Pro
Joined: Nov 2004
Posts: 601
Likes: 1
From: Wa
Is your car a auto or mn6? Sounds like a squeek in the vid. If its a MN6 might be the throwout bearing.. Mine use to squeek all the time till i replaced it... I just a had a resent problem with lifters and it did not even sound liek that it was more of a hollow tap tap tap not a squeek sound...
Thread Starter
Racer
Joined: Dec 1999
Posts: 442
Likes: 0
From: Dallas,TX,USA
The car is an A4. It sounds like a squeak on the vid, but the sound is actually more like a quick grind. The weird thing is when I am in the car the sound seems like it is right at the firewall. I will pull the covers off again and recheck. Is there any way to check for bad lifters? Will the car run without the belt?? Thanks
Pro
Joined: Nov 2004
Posts: 601
Likes: 1
From: Wa
Originally Posted by RunNE1
The car is an A4. It sounds like a squeak on the vid, but the sound is actually more like a quick grind. The weird thing is when I am in the car the sound seems like it is right at the firewall. I will pull the covers off again and recheck. Is there any way to check for bad lifters? Will the car run without the belt?? Thanks
Pro
Joined: Nov 2004
Posts: 601
Likes: 1
From: Wa
Originally Posted by sugarwolf
Well if its a grinding sound, it's either your flywheel grinding on stomthing, or somhow the lifter turned sideways and is running on the cam sidways or your timing chain is grinding on the cam retainer bolts ot the oil pump and last but not least the reluctor ring on the flywheel is grinding on the maincap which thats in the rear of the engine by the flywheel..
Thread Starter
Racer
Joined: Dec 1999
Posts: 442
Likes: 0
From: Dallas,TX,USA
Pulled the covers again. Could find nothing wrong. Against better judgement, I have been driving the car on an almost daily basis. If this were an engine problem(rod knock, spun bearing, bad lifter), would it not have already given up? Someone mentioned that a problem would show up as higer coolant temps, but I have not experienced that yet. Does not seem to misfire, no smoke. The more and more I get into this the more I realize a lift is almost a neccessity if you want to work on a Vette.
Am I right in assuming that the torque tube is constantly turning even when not in Drive? I am just trying to exhaust all possible checks before I take it apart, or send it off to the shop. Thanks
Am I right in assuming that the torque tube is constantly turning even when not in Drive? I am just trying to exhaust all possible checks before I take it apart, or send it off to the shop. Thanks
Le Mans Master
Joined: Feb 2006
Posts: 5,267
Likes: 40
From: Phoenix AZ
If the O2 code started with the knock, clear it and see if it comes back. Most likely a bad lifter, bent pushrod or broken rocker /spring. Pushrods are easy, just spin them to check for being straight. I have bent 2 and it sounded similar. With a stethoscope, I was able to pinpoint exactly which cylinder both times. Check the valve train side that corresponds with the bad O2 side.
Instructor
Joined: Aug 2003
Posts: 249
Likes: 1
From: Round Rock TX
Did you ever find the problem?
I'm having a problem that sounds very much like like yours. I finally figured out what it is, after weeks of looking.
My serpentine belt was partially off. Upon further inspection I found that the flywheel pulley/harmonic balancer had pushed back toward the motor. Here's a pic.
Is this your problem too? If so, how did you fix it? Did you take it to the dealer? What did it cost? If you did it yourself, can you share the instructions?
THANKS!
I'm having a problem that sounds very much like like yours. I finally figured out what it is, after weeks of looking.
My serpentine belt was partially off. Upon further inspection I found that the flywheel pulley/harmonic balancer had pushed back toward the motor. Here's a pic.
Is this your problem too? If so, how did you fix it? Did you take it to the dealer? What did it cost? If you did it yourself, can you share the instructions?
THANKS!
