C5 LS1 engine rattle when revving
Racer
Joined: Oct 2002
Posts: 396
Likes: 1
From: Coventry CT
What year is your car? the early c5s had two little tabs welded between
the cats. the tabs break and the two metal ends rub against each other and cause all kinds of noises at low rpm.
the cats. the tabs break and the two metal ends rub against each other and cause all kinds of noises at low rpm.
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.
Racer
Joined: Dec 2007
Posts: 416
Likes: 3
I'm wondering how all the ring lands were inspected, etc, then put back together only to later find a spun rod bearing?
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
I checked the piston tops by removing the heads. Looked for movement and cracks. Actually in my mind I was wondering If I could pull part of a piton top out.
I figured with noise, something had to be obviously broken and I would find it. It checked out fine. As it was.
I got new lifters, valve springs, timing chain, and some other stuff to throw parts at it to eliminate the things that my research turned up as issues for this noise.
To get the engine out of a C5 is not the same as a C4.
Pulling the pan off a C4 is nothing compared to a C5.
For your issue. Pull the pan off your LT1 and check. It is far easier then the heads.
Pulling an intake manifold off a C5, is easier then changing a tire.
It depends what you are working on, and chasing down.
Last edited by bill mcdonald; Jan 10, 2016 at 02:15 PM.
Racer
Joined: Jun 2015
Posts: 495
Likes: 36
From: Houston Texas
Just got this noise too, with the same symptoms...Competent corvette mechanic told me to get it towed to his shop. He said it could be something simple but that if its a broken valve spring or something and it drops in the engine then it could be catastrophic. So I dont even want to turn on the ignition to try anything out. Hopefully he can figure it out and fix it cost-effectively :/ Had the car for less than a year and kinda frustrated with something always going bad every other month. Pray that once this gets fixed, that I can at least get through some years with just normal maintenance and upkeep.
