C5 LS1 engine rattle when revving
Pro
Joined: Aug 2009
Posts: 662
Likes: 0
From: Loxahatchee FL
My guess would be the flex plate. Here's are pictures of the front flex plate assembly. The extra pieces bolted onto the standard looking flex plate are the adapter to clamp onto the input shaft of the torque tube. You can get some pretty bad noise if there's a crack in either of those plates.
http://www.ebay.com/itm/97-Corvette-...-/271101090467
I didn't see anything mentioned, so I'll ask if the noise changes with the car in gear vs out of gear?
http://www.ebay.com/itm/97-Corvette-...-/271101090467
I didn't see anything mentioned, so I'll ask if the noise changes with the car in gear vs out of gear?
Yes when not in gear everything sounds as it should, put in gear and get the sounds
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Even though I was only addressing nwaxtreme posts since this is his thread and you were thread jacking which just confuses the responses since no-one knows who a reply is addressed to, that would make me even more suspicious of the flex plate.
Pro
Joined: Aug 2009
Posts: 662
Likes: 0
From: Loxahatchee FL
****, sorry if that's what I did. I just thought with us having the same sound it was maybe adding more insight into what the OP was trying to figure out.
Ill stop and start a new one if no one finds an answer
Ill stop and start a new one if no one finds an answer
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
There's a line. Some of your posts were OK but responding to questions which were addressed to the OP giving your troubleshooting info is hijacking because it gets hard to follow what answers go with what posts. I first thought you were the OP posting that the sound changed in gear vs out of gear.
Burning Brakes
Joined: Jun 1999
Posts: 917
Likes: 10
From: on the beach in FL
Funny, mine just started this same unusual sound this morning. I have never heard it prior to now, only problem I have had was a squeaky belt which I thought might be a idler or tensioner. I sprayed some belt dressing on last night, squeak went away, then this morning this starts. Mine sounds as if it's on the driver side bank,only does the 'rattle" on quick burst of reving. I haven't tried replacing the idlers, but now I'm not sure if thats the problem? I only have 58,000 on the clock
Heel & Toe
Joined: Sep 2012
Posts: 23
Likes: 0
I think I might be having the same rattle, but it only does it when I accelerate on the road at low speeds. If I am sitting in park the rattle does not happen. At first I thought it might be my driver front wheel hub, but I ruled that out when it only rattles when I am driving and accelerate only not while coasting. I took it to the dealer and their tech could not figure it out, he thought it might be the harmonic balancer from previous experience, but they checked the whole suspension, pulleys and belts. Now I am completley baffled, I am thinking it may be a lifter out of adjustment, but like I said the rattling only occurs when there is a load on the transmission.
Does anybody have a suggestion! thanks in advance.
Does anybody have a suggestion! thanks in advance.
Drifting
Joined: Feb 2010
Posts: 1,720
Likes: 38
From: Colorado
I think I might be having the same rattle, but it only does it when I accelerate on the road at low speeds. If I am sitting in park the rattle does not happen. At first I thought it might be my driver front wheel hub, but I ruled that out when it only rattles when I am driving and accelerate only not while coasting. I took it to the dealer and their tech could not figure it out, he thought it might be the harmonic balancer from previous experience, but they checked the whole suspension, pulleys and belts. Now I am completley baffled, I am thinking it may be a lifter out of adjustment, but like I said the rattling only occurs when there is a load on the transmission.
Does anybody have a suggestion! thanks in advance.
Does anybody have a suggestion! thanks in advance.
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Heel & Toe
Joined: Sep 2012
Posts: 23
Likes: 0
you know what the flex plate makes a lot of sense!! because the rattling I am having only occurs when my car is in gear and driving with the accelerator depressed. Probably why the tech couldn't figure it out, you can't strap yourself under the car while it is driving lol
Burning Brakes
Joined: Jun 1999
Posts: 917
Likes: 10
From: on the beach in FL
Problem Solved! : Well I believe I found the root of the rattle noise. I have never changed my belts, although they didn't look bad, and with only 58,000 on the clock. I did have that nasty squeak and thought it might be a idler or tensioner going bad, so I just hit the pulleys with some belt dressing. BAD IDEA, apparently that makes the belts really tacky which did stop the squeak, but causes another problem. The alternator has a decoupling pulley on it (at least on the A4's) and when reving it rattles like a shaking a spray can. When you don't have a load on the engine, it's barely noticable, if at all. I am replacing the belts with gatorbacks tonight,(found a local autoparts that has them in stock), but I may have to replace the alternator due to a spun bearing on this pulley. You can replace only the pulley, but for basically $40 more you could have all new and since it's now 12 years old, figured why not. The video I found on you tube may not be the same noise as mine, but it's real close. Anyway hope this may help others with trying to pinpoint the rattle noise, since when it does rattle loudly, it transfer the sound up through the engine, almost making sound like an internal problem.
Thread Starter
Cruising
Joined: Feb 2013
Posts: 14
Likes: 0
Honestly not yet. I was going to just replace the factory manifold gasket but I've noticed the factory exhaust manifolds are rusty, and one is sooty at the weld near the flange. Dont think I will go through the trouble of replacing the gasket on those. So my plan is to order some shorty ceramic headers and install them in place of the factory. It is almost positively an exhaust leak since the tick gets louder at normal operating temperature. I will wrap this up in the next week or so and post a reply.
Drifting
Joined: Apr 2009
Posts: 1,898
Likes: 9
From: Morrisville PA
Honestly not yet. I was going to just replace the factory manifold gasket but I've noticed the factory exhaust manifolds are rusty, and one is sooty at the weld near the flange. Dont think I will go through the trouble of replacing the gasket on those. So my plan is to order some shorty ceramic headers and install them in place of the factory. It is almost positively an exhaust leak since the tick gets louder at normal operating temperature. I will wrap this up in the next week or so and post a reply.
You can get the entire setup used for $300-350.
1st Gear
Joined: Oct 2013
Posts: 1
Likes: 0
Noisy
Don't get rid of it over that noise, please! Would you do that to a Jeep?
I wish I could be of more help, and I am confident that if I could check out the car in person, I could pinpoint the source of the noise, but it is tough to do so with only a video and some info to go off of.
My opinion is that it is NOT piston slap. It sounds like a worn-out bearing in a pulley to me, but I know you have already removed the belts and replaced the idler pulleys, with no change.
I would recommend finding the best shop in your area and letting them have a look at it. You should be able to bring it to a shop that will not charge you much, if anything, unless they are able to fix/pinpoint the noise.
I wish I could be of more help, and I am confident that if I could check out the car in person, I could pinpoint the source of the noise, but it is tough to do so with only a video and some info to go off of.
My opinion is that it is NOT piston slap. It sounds like a worn-out bearing in a pulley to me, but I know you have already removed the belts and replaced the idler pulleys, with no change.
I would recommend finding the best shop in your area and letting them have a look at it. You should be able to bring it to a shop that will not charge you much, if anything, unless they are able to fix/pinpoint the noise.
So I am very perplexed, because the car/engine has only 61000 miles and it has done this since 17.000 miles. I think I am just going to sell the damn thing. Very frustrated.
Last edited by greydon; Mar 21, 2014 at 09:35 PM. Reason: SP
Safety Car
Joined: Jan 2014
Posts: 4,496
Likes: 856
From: Walhalla South Carolina
My c5 with 46,000 miles has a similar noise as does my 04 tundra truck I bought new with 39,000 miles when cold. I don't worry about it,take it through the gears and get into it. My feeling is if it is something serious it will break and then you will know. Some vetts have some quirky issues and noises that are just that quirky, no real damaging effects. Let us know what you find out.
Racer
Joined: Oct 2014
Posts: 438
Likes: 82
I'm having a similar issue as many describe in this thread. Bumping this one because the issue has been beaten to hell and I feel bad starting a new one. If anyone has any insight, please share..
Basically there's a rattle sound somewhere under heavy load. Similar to the 'marble in a can' sound, but I'd say it's more like pellets in a can.
Happens only when engine is under very heavy load - such as low RPM plus heavy throttle, or when engine is really opened it up.
I've had numerous cars make the same exact sound. My Subaru has had the same sound under the same conditions for the last 80K+ miles. Just a rattle on acceleration. Vette has 70K miles, the Subaru is up to 210K and despite the rattle there's been no engine trouble whatsoever. No loss of power, no sound at idle, no sound on light acceleration...it's strictly under heavy load.
Is this an exhaust problem? Busted cats or manifold..? Or maybe simply exhaust rattle?
I'm considering getting an some hi-flow cats slapped on and going from there.. the sound is awfully annoying, even though it's more than likely nothing serious.
Basically there's a rattle sound somewhere under heavy load. Similar to the 'marble in a can' sound, but I'd say it's more like pellets in a can.
Happens only when engine is under very heavy load - such as low RPM plus heavy throttle, or when engine is really opened it up.
I've had numerous cars make the same exact sound. My Subaru has had the same sound under the same conditions for the last 80K+ miles. Just a rattle on acceleration. Vette has 70K miles, the Subaru is up to 210K and despite the rattle there's been no engine trouble whatsoever. No loss of power, no sound at idle, no sound on light acceleration...it's strictly under heavy load.
Is this an exhaust problem? Busted cats or manifold..? Or maybe simply exhaust rattle?
I'm considering getting an some hi-flow cats slapped on and going from there.. the sound is awfully annoying, even though it's more than likely nothing serious.
Last edited by RueBurgundy; Jun 5, 2015 at 01:31 PM.
Racer
Joined: Mar 2011
Posts: 420
Likes: 13
From: West Deptford NJ
I'm having a similar issue as many describe in this thread. Bumping this one because the issue has been beaten to hell and I feel bad starting a new one. If anyone has any insight, please share..
Basically there's a rattle sound somewhere under heavy load. Similar to the 'marble in a can' sound, but I'd say it's more like pellets in a can.
Happens only when engine is under very heavy load - such as low RPM plus heavy throttle, or when engine is really opened it up.
I've had numerous cars make the same exact sound. My Subaru has had the same sound under the same conditions for the last 80K+ miles. Just a rattle on acceleration. Vette has 70K miles, the Subaru is up to 210K and despite the rattle there's been no engine trouble whatsoever. No loss of power, no sound at idle, no sound on light acceleration...it's strictly under heavy load.
Is this an exhaust problem? Busted cats or manifold..? Or maybe simply exhaust rattle?
I'm considering getting an some hi-flow cats slapped on and going from there.. the sound is awfully annoying, even though it's more than likely nothing serious.
Basically there's a rattle sound somewhere under heavy load. Similar to the 'marble in a can' sound, but I'd say it's more like pellets in a can.
Happens only when engine is under very heavy load - such as low RPM plus heavy throttle, or when engine is really opened it up.
I've had numerous cars make the same exact sound. My Subaru has had the same sound under the same conditions for the last 80K+ miles. Just a rattle on acceleration. Vette has 70K miles, the Subaru is up to 210K and despite the rattle there's been no engine trouble whatsoever. No loss of power, no sound at idle, no sound on light acceleration...it's strictly under heavy load.
Is this an exhaust problem? Busted cats or manifold..? Or maybe simply exhaust rattle?
I'm considering getting an some hi-flow cats slapped on and going from there.. the sound is awfully annoying, even though it's more than likely nothing serious.
You might consider changing spark plugs. I went with NGK TR5IX gapped at .040. I was previously using NGK TR55 gapped at .055 and out of the blue started having detonation issues. I think the gap is to big with a stock tune.
Might as well change wires as well. I went with GMPP 12495519 plug wires.
Check for vacuum leaks. Is your cooling system operating properly? Use a quality premium fuel, Top Tier Gasoline.
Last edited by jlaw1313@comcast.net; Jun 12, 2015 at 08:18 AM.