• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Engine Starting Knock/ping

RTRSAVALANCHE

Full Member
Joined
Jun 12, 2002
Messages
15
Location
Des Monines WA
Has anyone ran into when they start their AV after it sits for several moments there is a knocking sound as it starts. It sounds like the valves knocking it only last a second or so. I own a 1500 with the 5.3 just wondering if this is a characteristic of the 5.3?
 

gpfahler

Charter Member
SM 2003
Full Member
Joined
Mar 2, 2002
Messages
715
Location
Southern Calif
First, go to your profile and put in the info on your vehicle, If you have the 2500 with the 8.1 it appears to be a normal thing. I have not heard of this problem with the 5.3.

Gary
 

marc_w

Full Member
Joined
Jun 5, 2002
Messages
1,112
Location
Douglas, MA
My Blazers's 4.3 has done this since new... Even after it's warm (now at 90K), I still have the same soft little randon but rhythmic (sp?) "tick tick tock tap tick tick tap" noise at idle. Sounds just like a lifter is out of adjustment.

I know it's not an Av, but the have similar engines...
 
A

AVALANCHE_JIM

GUEST
I read in Motor Trends There've been alot of complaints about cold-start knock in the Vortec engine family, ang most General Motor's customers are getting incomplete answers at dealerships. We've spoken with Matt Kester, assistant manager with GM Powertrain Product Communications, about the situation. He said GM engineers are aware of the problem and are currently in a reaserch stage. The cold-start knock involves the 4.8L, 5.3L, and 6.0L V-8s in all applicable GM & trucks from '99 to '02. They believe the cause is carbon buildup on the circumference of the piston above the top piston ring. This interference is affecting the dynamics of piston travel and therfore causing a knock. I found this interesting
 
F

firstchevy

GUEST
Go the website www.rv.com There are a large number of postings related to problems with the new chevrolet vortex engines. Even has a name "piston slap". The implication is that there is a fundamental problem with the design of the engines. I hope this is not the case....I just boght my first Chevy...Avalanche 2500 with all the trimmings. Plan to tow a travel trailer.

:6:
 

Crexis

Full Member
Joined
May 13, 2002
Messages
588
Location
Tucson, AZ
I seem to get one knock on a cold start, but my mother has a '00 Tahoe that's done the same thing for 65,000 miles with no problems, so I'm not terribly worried.
 

Chief

CAFCNA FOUNDER
Charter Member
SM 2008
SM 2007
SM 2006
SM 2005
SM 2004
SM 2003
Full Member
Joined
Jan 10, 2002
Messages
12,693
Location
Edmonds, WA
firstchevy said:
Go the website www.rv.com ? There are a large number of postings related to problems with the new chevrolet vortex engines. ?Even has a name "piston slap". ?The implication is that there is a fundamental problem with the design of the engines. ?I hope this is not the case....I just boght my first Chevy...Avalanche 2500 with all the trimmings. ?Plan to tow a travel trailer.

:6:

The charges of "piston slap" are laregly brought on by one person who will stir it up and talk to anyone that will listen to him in any forum. If there was fatal design problem in the 6.0 or 5.3 - an engine sitting under the hood of a wide range of GM products from 99 on up - their 2002 JD Powers ranking would not be third best IN THE WORLD for vehicle quality.

Piston slap and the fatal flaw is nothing more than hype from GM detractors. I love my 5.3 liter V-8, made me realize dad was right. There is no substitute for cubic inches (unless you have an 8.1 and then the cubic inches get kind of silly above that)
 

gandolphxx

Charter Member
Full Member
Joined
Jan 24, 2002
Messages
5,750
Location
Houston, TX
This "piston slap" thing has been blown way out proportion and dragged from board to board by the same group with their own agenda, whatever it is.

I have a 2500 that has "been rode hard and ..." - doesn't guzzle oil, doesn't knock and I am the only smoker of the pair. Maybe it has to do with my breakin policy, the 8100's are hauling loads all over the country and drag racing occasionally ;D

If you want an education on the 8100, and what it is made of check this standard 8100 vs the marine version

"Finally, and of prime importance to boaters, both versions of the 8100 were engineered with an eye toward durability. In fact, GM?s marine-engine standards surpass those required for its truck applications. In one test the engine was run in 60-minute cycles?wide-open throttle for 55 minutes, then idle for five minutes?nonstop for 300 hours, far exceeding the use the engine might get under normal operation. " - the time was to refill the tanks ;D

BTW, 5300 folks don't read this.
 

steelheadchaser

Staff member
Administrator
Moderator
Charter Member
PM 2021
PM 2020
PM 2019
PM 2018
PM 2017
PM 2016
PM 2015
PM 2014
PM 2013
PM 2012
SM 2011
SM 2010
SM 2009
SM 2008
SM 2007
SM 2006
SM 2005
SM 2004
SM 2003
Full Member
Joined
Apr 14, 2002
Messages
10,444
Location
Pacific Northwet
As far as the 5.3L goes, Chev has been making the small block in one form or another continuosly since 1955 (although the block in 1955 was different than subsequent years). The notion that there are "design flaws" that cause piston slap in the new engines is beyond laughable.
 
J

jeff-ar

GUEST
Just bought my AV sat now has 522 miles and I noticed the same knock for about the 2 seconds on start up. Hopefully, they will figure out the problem at GM.
 

gandolphxx

Charter Member
Full Member
Joined
Jan 24, 2002
Messages
5,750
Location
Houston, TX
welcome to the board jeff-ar, your engine is still breaking in - if you have a chance scan the multitude of posts and you will discover that Gm doesn't have a problem to be fixed - if you really want to get nervous checkout some of the Ford and Dodge sites. ;D
 
G

got_change

GUEST
As Istart my 5.3 av hot or cold It starts on what I hear to be a spark knock, or an advanced timing only for as long as it takes to light up ---that seems to be computer controlled BUT many times especially if it sits a day or two it'll light up and tick tick tick tick almost like a lifter bled down, but after you listen to it a few times It does sound like cold piston slap like the guys at the chevy dealer told me . I wonder why one cylinder and is that tick accelerated wear on my 5.3?
 

frule

Charter Member
SM 2003
Full Member
Joined
Feb 2, 2002
Messages
171
Location
Knoxville,TN
I have had this sound occur a few times and it sure doesn't sound like a lifter or ANY type of valvetrain noise.I'd describe it as a rattling sound,not a ticking sound.More like a diesel engine,very brief in duration,and I've only heard it when standing outside the Av when my wife started the truck.
The piston slap is theory sounds correct to me.I have run both dino and synthetic oils and that made no difference.I really doubt the "carbon on top of the pistons idea" in such a new engine.
I just hope GM is correct when they say it won't affect durability! :B:
 
Top