Knocking when cold
Thread Starter
Teching In
Joined: Apr 2007
Posts: 43
Likes: 0
From: New Mexico
Knocking when cold 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
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
Trending Topics
Thread Starter
Teching In
Joined: Apr 2007
Posts: 43
Likes: 0
From: New Mexico
Originally Posted by 02 Pewter SS
I had it bad too, 35k here.. My last oil change to amsoil made it almsot disappear.
Thanks Again,
Nick
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
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).
The oil I'm running is Valvoline Durablend 10W30 (it's hot in Arizona).
Staging Lane
Joined: Feb 2007
Posts: 64
Likes: 0
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
Aaron
Thread Starter
Teching In
Joined: Apr 2007
Posts: 43
Likes: 0
From: New Mexico
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. 
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.
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.
Staging Lane
Joined: Feb 2007
Posts: 64
Likes: 0
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.