engine getting noisy
Thread Starter
Racer
Joined: Jan 2007
Posts: 265
Likes: 1
From: san diego california
engine getting noisy
I have a 2002 C5 with about 70,000 miles. I have had what I thought was possible lifter noise, but it no longer seens to fit that description. Usually after running the car, stopping, and then restarting, the noise gets worse. It doesn't seem to be going away when the car is warmed up, but it is intermittent, but more often now I hear it.
I was using a diagnostic wand to listen to the engine, and really wasn't finding much until I dropped the wand. When I got down to pick it up, the sound was much louder, which seems to me to indicate it is in the lower section of the engine. It is not the "click" or "snick" of a lifter, but more a metallic "clank" or "dank" if those descriptions make any sense. Performance-wise I have no issues, but I also don't want something to explode in the engine. I'll probably take it in to the stealer next week, but wondered if anyone had an idea.....I believe it increases with the RPMs, but as the RPMs go up, the noise seems to lessen. I'm kinda stumped....maybe it is the infamous piston slap?
I was using a diagnostic wand to listen to the engine, and really wasn't finding much until I dropped the wand. When I got down to pick it up, the sound was much louder, which seems to me to indicate it is in the lower section of the engine. It is not the "click" or "snick" of a lifter, but more a metallic "clank" or "dank" if those descriptions make any sense. Performance-wise I have no issues, but I also don't want something to explode in the engine. I'll probably take it in to the stealer next week, but wondered if anyone had an idea.....I believe it increases with the RPMs, but as the RPMs go up, the noise seems to lessen. I'm kinda stumped....maybe it is the infamous piston slap?
Le Mans Master
Joined: Jan 2007
Posts: 7,364
Likes: 6
From: Rocky Mount Virginia
Possibly a bearing going bad. Hope not. When was the last time the oil was changed? Change it again and check for metallic flakes on the drain plug. Also how does the oil pressure look?
Thread Starter
Racer
Joined: Jan 2007
Posts: 265
Likes: 1
From: san diego california
engine noise
I will be changing the oil next week....oil pressure is fine, hovers around 40 lbs and up to around 60 when I jump on it. I'll check for metallic particles, good hint. Probably will take it to the local Chevy dealer first, though there is a Vette specialist not too far away, will try them before the stealer. All I can say is it doesn't sound very good....it clatters quite a bit. At least I have an extended warranty, so if it is bad, my fee won't be too bad.
Le Mans Master
Joined: Jan 2007
Posts: 7,364
Likes: 6
From: Rocky Mount Virginia
Hopefully it's not, but if it is good thing your have that warranty. Usually rod bearing noise would be like rapping your knuckle on a desk, it really isn't metallic sounding, just a deep thump. So maybe not a bearing. Is it more in the front or rear of the motor?
Thread Starter
Racer
Joined: Jan 2007
Posts: 265
Likes: 1
From: san diego california
it seemed to be more from the rear....my plan was to do the oil change yesterday, and I can put it up on the lift, at which time I could really listen to the noise. I may just do it this coming Wednesday, won't have time before then. It does not get louder when I rev, and actually seemed to go away and then return at idle if I rev up around 5 g's. Last time I took it to the dealer, of course it made no noise at all, lol...
It sounds more like a diesel engine knock....if that makes sense. Which is why I thought it might be normal Corvette engine noise, but it has been progressively getting louder, and I figure that means it is getting worse
It sounds more like a diesel engine knock....if that makes sense. Which is why I thought it might be normal Corvette engine noise, but it has been progressively getting louder, and I figure that means it is getting worse
Le Mans Master
Joined: Jan 2007
Posts: 7,364
Likes: 6
From: Rocky Mount Virginia
If you're going to take it to the dealer, baby it until then. No revving of any kind. You don't want to throw a rod thru the block. LS1's are strong motors, and a rod bearing failure is rare.
Good Luck!
Good Luck!
Racer
Joined: Sep 2006
Posts: 280
Likes: 0
I have a 2002 C5 with about 70,000 miles. I have had what I thought was possible lifter noise, but it no longer seens to fit that description. Usually after running the car, stopping, and then restarting, the noise gets worse. It doesn't seem to be going away when the car is warmed up, but it is intermittent, but more often now I hear it.
I was using a diagnostic wand to listen to the engine, and really wasn't finding much until I dropped the wand. When I got down to pick it up, the sound was much louder, which seems to me to indicate it is in the lower section of the engine. It is not the "click" or "snick" of a lifter, but more a metallic "clank" or "dank" if those descriptions make any sense. Performance-wise I have no issues, but I also don't want something to explode in the engine. I'll probably take it in to the stealer next week, but wondered if anyone had an idea.....I believe it increases with the RPMs, but as the RPMs go up, the noise seems to lessen. I'm kinda stumped....maybe it is the infamous piston slap?
I was using a diagnostic wand to listen to the engine, and really wasn't finding much until I dropped the wand. When I got down to pick it up, the sound was much louder, which seems to me to indicate it is in the lower section of the engine. It is not the "click" or "snick" of a lifter, but more a metallic "clank" or "dank" if those descriptions make any sense. Performance-wise I have no issues, but I also don't want something to explode in the engine. I'll probably take it in to the stealer next week, but wondered if anyone had an idea.....I believe it increases with the RPMs, but as the RPMs go up, the noise seems to lessen. I'm kinda stumped....maybe it is the infamous piston slap?
Ask me how I know all this!!
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Thread Starter
Racer
Joined: Jan 2007
Posts: 265
Likes: 1
From: san diego california
Will follow up
Thanks for the info on the alternator/water pump. Tomorrow I am changing oil, and while I have the car on the lift, I will use the diagnostic wand to listen around and see if I can pinpoint the noise. Once I figure out what it is, I'll let ya'll know! 
Instructor
Joined: Dec 2006
Posts: 244
Likes: 0
From: Phoenix AZ
If it's a rod bearing, they go from bad to worse very fast and more noticeable when adding throttle, quieter under decel or idle.
If it's an accessory (water pump or AC or...) it will be rpm related also, a lighter noise, and can take a week or so to get really loud as opposed to rod bearings that can get really loud just driving home from a few miles away.
Wheel bearing/drivetrain related are speed related .. faster the wheel turns, more frequent the sound is. U-joint/rear-end play can be checked by first gear idling along, ease on-off the gas and listen for 'clunk' sounds. There shouldn't be any.
Wheel bearings also go south in a hurry, ..a couple days of driving back an forth to work with each day getting noticeably louder.
Then there's chassis rattles, suspension noise .. -grin- ..all kinda things that go 'bump' in the night
-Frank
If it's an accessory (water pump or AC or...) it will be rpm related also, a lighter noise, and can take a week or so to get really loud as opposed to rod bearings that can get really loud just driving home from a few miles away.
Wheel bearing/drivetrain related are speed related .. faster the wheel turns, more frequent the sound is. U-joint/rear-end play can be checked by first gear idling along, ease on-off the gas and listen for 'clunk' sounds. There shouldn't be any.
Wheel bearings also go south in a hurry, ..a couple days of driving back an forth to work with each day getting noticeably louder.
Then there's chassis rattles, suspension noise .. -grin- ..all kinda things that go 'bump' in the night
-Frank
Thread Starter
Racer
Joined: Jan 2007
Posts: 265
Likes: 1
From: san diego california
Engine noise may be resolved....
I took the Vette in to Top Flight Corvette here in San Diego. Initial thought was a possible rocker arm, probably due to the TSA regarding the "O" ring being cut. However, after changing oil and putting Amsoil in, the noise seems to be significantly reduced to the point where when Top Flight did a diagnostic on my fuel and spark system prior to having a computer tune completed (my Vette pings under heavy load), they apparently did not hear anything unusual. So for now, although it still seems a little mystery, it has diminished to the point of "normal" Vette noise.
Sure was nice checking out the new C6 on the rack....oh to be able to afford a Z06.
Sure was nice checking out the new C6 on the rack....oh to be able to afford a Z06.
