I noticed something about my car recently...an odd noise and I don't know what it is. I know what the piston slap sounds like(thanks GM ) but I'm also hearing something else.

Let's say I drive the car for a while, run into the store or into the house and let it sit for a few minutes. I come out and start it up and start driving. I notice this weird sound(it also does it when the motor is cold in the morning). I'll give the car some go then when I let off I get the faint sound of a sewing machine. It does it worse after starting the car...and naturally goes away after a few minutes/miles of driving.

It sounds to me like the lifters are chattering but I don't know. Like I said it goes away after a few minutes.

Am I going nuts or has anyone else heard this before? I know it's not piston slap, I know what that sounds like unfortunately . The more and more I listen the more and more I realize LS1's are quiet motors lol.

BTW, the car runs fine...gas mileage is going down a bit but I think she just needs a good tune up.

Any opinions?

Thanks guys

 

Anyone?

 

Could be lifter noise. I thought I had piston slap till i realized its tapping at half crank speed, so I figure it to be a lifter. Switching back to mobil1 from GC has actually quieted down the tapping on cold startup. (not that I suggest mobil1 over GC, I just cant get GC anymore)

 

What bothers me is that I could be driving all day and have it shut off for 10-15 minutes and it'll still make that noise.

If a bunch of people here tell me not to worry then I won't...I just don't like hearing funny noises from my motor lol

 

Mine's the same way... shut it off even for just a couple of minutes and it makes that noise. Even weirder is that on a cold start, its quiet for the first 30 - 45 seconds, then it starts chattering, and after it warms up completely its quiet again. It sounds loud but muffled from the bottom, its quieter but a crisp sharp noise from the top of the motor. I really dont know what it is with any certainty, but ive had the noise for the last 50K on a 74K mile engine. Ill see how a cam swap affects the noise next month.

Must only affect guys named tony.

 

Mine is the same exact way.

....and yeah...it must be a Tony thing

 

my car is the same way. going to do a h/c swap hopefully it goes away.

 

Mine's indentical. After my cam swap, about 18 months ago, it was quiet and it stayed quiet. It seems like it started happening about 6 months ago when I put on MAC's w/ORY, Ported TB, and LS6 intake. Maybe since it breathes easier with these upgrades, well, maybe the working parts of the motor aren't getting the back-pressure they need to keep the motor 'tight'.

Anybody think this makes sense or is just plain stupid?

 

same thing happened to me... my dad thought it was a lifter too. i took it into the dealer, they did their diagnostic stuff. turns out it was bored crooked. they wanted to put spacers in, but that didnt fly with us. a week and a half later, i had a brand new engine. So if its still under waranty, i'd take it into your dealer. may not be the case with you, but better safe than sorry.

 

Mine Has A Funny Sound In The Morning Too!! I Just Figured It Takes A While For The Oil To Be Pumped Thru Out The Motor. It Sounds Like A Lifter Or A Rod Right?? AND MY NAME AINT TONY

 

Its the injectors.

 

no,dont think so.ls1's are known to sound like sewing machines.if it was always like that then thats your answer.if it suddenly started then pull the valve covers and check for loose rocker arms,and check your pushrods.

 

Mine has been doing this for 7-8 months and still sounds the same ... hasn't worsened, so, I'll just drive it and not worry about it ... will have a leak down test done ... to be safe.

 

I'm with ddnspider. My 2000 malibu (3.1L v-6) does the exact same thing, so it's not just LSX motors. I don't notice drop in gas mileage or anything of that nature, and it still runs (knock on wood) as strong now as it did 20k miles ago. Just a noisy valvetrain, and I'd attribute it to the lifters bleeding off oil at certain operating temps.

 

thats one thing some people forget... half crank speed...
guessing the lifter isnt pumping up until its hot..

 

mine was doing that as well, i would hear it when the revs were coming down, or when i would hit the brakes and come to a stop in neutral.

i took the valve cover off on the side that the noise was coming from and attempted to check the rods. i broke 2 sockets while trying to loosen the rocker bolt, so i didnt have any thing else to try and unbolt them. put it back together and started it up. now the noise is gone, and i haven't heard it since.

and i dont think i managed to budge the bolt.

 

Could be a broken spring or injectors....

 

I have Comp 918 springs and have pulled the valve covers ... not the springs. Injectors ... well, could be, but, wouldn't it do it ALL the time and not just at startup? BTW, the injectors are only about a year old.

The lifter theory seems to be the most likely. I'm finally scheduling a leakdown test to make sure one cylinder is not weaker than others. If they're all good, well, I'll just keep driving it hard. I think evrything's OK ... just valvetrain noise or something that's normal with some engines. My car only started making noise when I installed LS6 intake/ported TB, MAC headers, and ORY (all on the same weekend). Maybe it's valvetrain noise from gaining more power and the valvetrain being worked harder.

Probably something I'll never know.