Help with rattle noise from engine when cold
Thread Starter
Safety Car
Joined: Mar 2000
Posts: 4,395
Likes: 4
From: Anderson, IN
Help with rattle noise from engine when cold
I have an 06 MN6 with about 90K miles. I bought it with about 82K.
When the engine is cold I get a rattle noise that starts a little above 2500 RPM and continues to about 3500 RPM then goes away as RPM increases. This happens until the engine is at operating temperature, then I don't hear it again.
The noise sounds like the valvetrain, it seems like it's coming from the top of the engine, it's not down low. It's not very loud. Oil pressure is normal, oil is clean (no metal). I don't hear anything like this noise when it's at idle.
I'm thinking worn rockers, maybe lifters. Any ideas?
TIA
When the engine is cold I get a rattle noise that starts a little above 2500 RPM and continues to about 3500 RPM then goes away as RPM increases. This happens until the engine is at operating temperature, then I don't hear it again.
The noise sounds like the valvetrain, it seems like it's coming from the top of the engine, it's not down low. It's not very loud. Oil pressure is normal, oil is clean (no metal). I don't hear anything like this noise when it's at idle.
I'm thinking worn rockers, maybe lifters. Any ideas?
TIA
Racer
Joined: Nov 2006
Posts: 357
Likes: 42
From: Beverly Hills Florida
Sounds like the same thing I’ve been trying to figure out for a few months.
I hear it from the top rear of the engine but while driving and only while the car is in gear and under power, not when I let off the gas.
The sound goes away after the engine worms up.
I figure it might be the exhaust manifold or something related to it.
That expands when it get hot and stops rattling.
I hear it from the top rear of the engine but while driving and only while the car is in gear and under power, not when I let off the gas.
The sound goes away after the engine worms up.
I figure it might be the exhaust manifold or something related to it.
That expands when it get hot and stops rattling.
Drifting
Joined: Jul 2005
Posts: 1,630
Likes: 188
From: Austin TX
The LS2 motor is known for a ticking noise in the valvetrain. There are a few threads on the forums about it. Not sure if this is the same problem you are experiencing but could be. My 05 has done it for years.
Heel & Toe
Joined: Aug 2017
Posts: 15
Likes: 2
From: Edgewater Florida
I have an 06 MN6 with about 90K miles. I bought it with about 82K.
When the engine is cold I get a rattle noise that starts a little above 2500 RPM and continues to about 3500 RPM then goes away as RPM increases. This happens until the engine is at operating temperature, then I don't hear it again.
The noise sounds like the valvetrain, it seems like it's coming from the top of the engine, it's not down low. It's not very loud. Oil pressure is normal, oil is clean (no metal). I don't hear anything like this noise when it's at idle.
I'm thinking worn rockers, maybe lifters. Any ideas?
TIA
When the engine is cold I get a rattle noise that starts a little above 2500 RPM and continues to about 3500 RPM then goes away as RPM increases. This happens until the engine is at operating temperature, then I don't hear it again.
The noise sounds like the valvetrain, it seems like it's coming from the top of the engine, it's not down low. It's not very loud. Oil pressure is normal, oil is clean (no metal). I don't hear anything like this noise when it's at idle.
I'm thinking worn rockers, maybe lifters. Any ideas?
TIA
Last edited by G8RC6; Nov 20, 2017 at 06:13 PM.
Instructor
Joined: Mar 2016
Posts: 189
Likes: 50
From: Martinez GA
Even though it sounds like the noise is emanating from the top of the engine, it could well be caused by piston slap. LS engines are notorious for having audible piston slap during warmup. The cause is the large tolerance between the aluminum pistons and the steel cylinder sleeves which is built in by design. Aluminum expands more than steel when heated. So once the pistons become hot, they expand. The steel sleeve also expands a little. After expansion, the piston to sleeve tolerance is closed enough to eliminate the noise caused by piston slap.
Mine does this too. All is good once it starts to warm up.
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Instructor
Joined: Jul 2017
Posts: 102
Likes: 12
From: Lexington Kentucky
Engine noise
Have a 2005 with 96,000 miles that does the same engine rattle around 2500 rpm. Been chasing the noise for some time. If it is piston slap won't it eventually destroy a piston skirt ? Is there a solution ? Better pistons with tighter tolerances ?
Racer
Joined: Nov 2006
Posts: 357
Likes: 42
From: Beverly Hills Florida
8th Gear
Joined: Sep 2006
Posts: 8
Likes: 0
From: Norman Oklahoma
Engine Compartment Rattle
I have an 06 MN6 with about 90K miles. I bought it with about 82K.
When the engine is cold I get a rattle noise that starts a little above 2500 RPM and continues to about 3500 RPM then goes away as RPM increases. This happens until the engine is at operating temperature, then I don't hear it again.
The noise sounds like the valvetrain, it seems like it's coming from the top of the engine, it's not down low. It's not very loud. Oil pressure is normal, oil is clean (no metal). I don't hear anything like this noise when it's at idle.
I'm thinking worn rockers, maybe lifters. Any ideas?
TIA
When the engine is cold I get a rattle noise that starts a little above 2500 RPM and continues to about 3500 RPM then goes away as RPM increases. This happens until the engine is at operating temperature, then I don't hear it again.
The noise sounds like the valvetrain, it seems like it's coming from the top of the engine, it's not down low. It's not very loud. Oil pressure is normal, oil is clean (no metal). I don't hear anything like this noise when it's at idle.
I'm thinking worn rockers, maybe lifters. Any ideas?
TIA