C7 Engine Noise
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C7 Engine Noise
My 2014 C7 has developed a engine noise that sounds like a bad bearing in a alternator or water pump. My Vette convertible has the Z51 and Performance Exhaust pkg's. Current milage is 1,900. The noise can be heard with engine hot or just after starting. Turning off A/C and Performance Exhaust makes no difference. Noise does not change with RPM so it would appear to not be the new variable valve system. There are no dashboard warnings nor error checks per my Chevy dealer who is scratching his head over what it could be. No GM service advisories, etc.
can be found. The noise is somewhat new as it was not there when I took Museum delivery and miles added since. It appears to not be the dry sump which bulletins say can be noisy.
Anyone experience this and what the cause was ??? Thanx.
can be found. The noise is somewhat new as it was not there when I took Museum delivery and miles added since. It appears to not be the dry sump which bulletins say can be noisy.
Anyone experience this and what the cause was ??? Thanx.
Race Director
Joined: May 2008
Posts: 10,742
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From: Manheim Pennsylvania
Everything I can think of would change with rpm or amount of air flowing in the intake system. Even exhaust flow changes with power added or subtracted. You say it is like a howl, how loud? Does it start immediately when the engine starts or take a minute or so to develop. Only thing I can think of is something electrical that as current is applied resonates a frequency that sounds like a howl. That would not change with engine power/rpm change. Take a large screwdriver and use it as a stethoscope by holding the screw tip on engine components and placing your ear near/on the handle. Yea, sounds odd, it really works! Maybe you can narrow the sound down to an engine component.
Last edited by Larry/car; Oct 3, 2014 at 06:14 PM.
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Navigator
Joined: Jul 2013
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Everything I can think of would change with rpm or amount of air flowing in the intake system. Even exhaust flow changes with power added or subtracted. You say it is like a howl, how loud? Does it start immediately when the engine starts or take a minute or so to develop. Only thing I can think of is something electrical that as current is applied resonates a frequency that sounds like a howl. That would not change with engine power/rpm change. Take a large screwdriver and use it as a stethoscope by holding the screw tip on engine components and placing your ear near/on the handle. Yea, sounds odd, it really works! Maybe you can narrow the sound down to an engine component.
Race Director
Joined: May 2008
Posts: 10,742
Likes: 629
From: Manheim Pennsylvania
The noise is heard at idle. Either right after a cold start or after any trip distance with engine hot. It is a rhythmic mechanical noise that sounds like a bad alternator or water pump from my decades of automotive experience. I did use a auto stethoscope topside around engine cavity and found no localization for noise source. You can hear it up to 100 feet away. It appears that the front wheel wells act like a megaphone to project out. I have attached a mp3 file of the noise recording. You will hear it distinctly on top of the base engine idle sound.
Cruising
Joined: Aug 2014
Posts: 13
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From: San Bernardino California
The mp3 file will not play on my macbook using itunes, quicktime or VLC.
I have a C5 with 50k miles which makes a sound like a bad alternator bearing or PS pump bearing. When I cold start the car, the sound is not there and then abruptly appears after about 45 seconds or so. I' going to start my own thread in the C5 forum but since I recorded the sound, I thought that it might help if it sounds like yours does.
Good luck!
I have a C5 with 50k miles which makes a sound like a bad alternator bearing or PS pump bearing. When I cold start the car, the sound is not there and then abruptly appears after about 45 seconds or so. I' going to start my own thread in the C5 forum but since I recorded the sound, I thought that it might help if it sounds like yours does.
Good luck!
Burning Brakes
Joined: Aug 2014
Posts: 990
Likes: 207
From: Bay Area CA
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Instructor
Joined: Nov 2006
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From: Rancho Mission Viejo, CA
I had a loud, grinding sound coming from the aft part of the engine, and I could only hear it at idle. It ended up being a bad torque tube. After the torque tube was replaced I no longer heard the sound.
Heel & Toe
Joined: Jun 2012
Posts: 23
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From: TN
Mine was one that had a rod bearing issue. I heard a small very faint chirping sounds (like an alternator bearing sound) before it complete went out. Started for a couple of days and then it died. It was very faint and I was surprised when it did go out. The noise was inconsistent of RPMs, gears, etc..I have a 2014 convertible Z51 auto.
I listened to your audio but did not hear anything that sounded like it. But I was thinking alternator bearing when I heard mine. Hope it is nothing for you.
I listened to your audio but did not hear anything that sounded like it. But I was thinking alternator bearing when I heard mine. Hope it is nothing for you.