Daytona Yellow 69 Z/

Hi all,
I am very new to the late model cars and have only had my 2000 SS for a few weeks. My question is... When I first start the car when it is cold it has a loud knocking sound but once it gets to nomal temp it is gone. someone told me the LS1s have bad valvetrain noise, but It doesnt sound like that to me. could it be piston slap? the car has 69k miles on it. the car has desent oil presure so I dont think that is the issue. A long time ago I had a power steering pump that made a similar knocking sound on a 67 Camaro, Has anyone had this happen to them?

Any idea with out hearing it what might be happening??
Thanks in advance,
Nick

sbusby

I have the same thing happening

Optimus_Prime

iTrader: (4)

My vote goes to piston slap

fuseone

that would be piston slap

Daytona Yellow 69 Z/

Thanks guys,
Is that common with the LS1 cars? hard to believe with only 69K it would allready have piston slap.

Thanks Again,
Nick

l337_haxs

iTrader: (1)

Mine has it at 64k and my buddy at 32k has it as well

02 Pewter SS

I had it bad too, 35k here.. My last oil change to amsoil made it almsot disappear.

Daytona Yellow 69 Z/

wow, must be common to these cars. The car will need the oil changed in about 1000 miles and I will try Moble One and see if that helps. I dont really know where to get Amsoil around here. What weight oil are you using?

Thanks Again,
Nick

Desert Rat

iTrader: (1)

I have it too. Is this anything to be concerned about? These are some low mileage engines that have this issue. Mine only has 55k.

The oil I'm running is Valvoline Durablend 10W30 (it's hot in Arizona).

slikrider20

iTrader: (9)

Knocking? Exactly what is that?

LS199Z28

Go to www.pistonslap.com there is a whole lot of information on this subject. Most GM engines from 1999-2006 3.1, 3.4, 4.3, 4.6 (Northstar), 4.8, 5.3, 5.7(LS1), 6.0 or 8.1 liter engine have this problem. Some how I got lucky with my 99 Z28 I have not had any piston slap with it, the motor is at 68000 miles, I am planning a full engine rebuild with forged pistons and rods from EPP within the next year or so. I hope this information helps

Aaron

slikrider20

iTrader: (9)

I couldnt get the sample audio clilp to work, but i havent heard any weird sounds comin from my engine. Does it do it on idle or at higher RPM's?

Daytona Yellow 69 Z/

Mine makes the sounds at basicly any rpm when cold. Now when it warms up itis gone and sounds good. Unfortunatly when I bought the car the engine was allready warm, so I didnt hear anything untill I was 2 states away the following morning.

01T-TopToy

iTrader: (5)

I have had piston slap since I got it with 31k on it, it has not had ANY negative impact on the car. It has to do with tolerances on the piston-to-block clearances due to the forged pistons ( so I am told from some GM techs whom I trust ) something about the different rates of expansion on the materials in the piston and block and is Nothing to worry about, usually happens at start up, and decreases as the engine assembly warms up.
I lost a rod bearing at 60k (my fault for screwing about) did a complete rebuild and the machinist said I had no discernible wear on the cylinders. NADA. So if you have slap, don't worry about it, just don't hammer the holy beejezus out of it til it warms up.
I drive my car Hard and it's just not something I worry about. Use good oil and you'll be fine. In verbal terms it's sort of a duk-duk-duk sound ( say it fast and don't move your jaw much) and changes with rpms.
Hope that helps.

LS199Z28

It should sound like a diesel running if you have it, a buddy of mine had to get his motor rebuilt at 42000 miles, but he kept flooring the gas when the motor was not up to operating temp, not the best thing to do.