2001 GMC 6.0L 2500 HD piston noise

Chad · July 10, 2002

Have been hearing piston noise for some time now and the dealer says its normal anyone else have this noise? Cant be good for the motor.

Shaners · July 10, 2002

Chad, Welcome to the forum...

This was posted by "Wink" (who is one of our members), in the light duty forum yesterday...

BIG NEWS!

I just talked to the service manager at a small Chevy dealership near where I live now, there is a GM Service Bulletin that was issued 5/22/02 that discusses the ping problem. It states that the rear knock sensor is probably defective and should be replaced. Mine is being replaced next tuesday morning. I'll report the result.

swl2126 · July 14, 2002

02-06-04-023; Audible Spark Knock

(Detonation), MIL Illuminated, DTC P0332

Set (Replace Rear Bank Knock Sensor and

RTV Area Around Sensor); 1998-2002

Chevrolet Camaro, Corvette, Pontiac Firebird

with 5.7L Engine (VIN G – RPO LS1), 1999-

2002 Chevrolet and GMC C/K Pickup and

Utility Models with 4.8L, 5.3L or 6.0L Engine

(VINs V, T, Z, N, U – RPOs LR4, LM7, L59,

LQ9, LQ4)

swl2126 · August 22, 2002

Are there any 2003 6.0L owners out there that are have the 'cold start knock'?

Back in June, TXDoc posted some information from Truck Trend magazine from Matt Kester, GM Powertrain, stating GM was aware of the problem and was trying to find a solution.

After several letters and e-mails, the GM Executive Office (anyone know who that is?) contacted me today. I explained my cold start issue and the reference to Mr. Kester's statement. He told me empatically that GM was not working on the problem and as far as they were concerned the problem is not detrimental to the longevity of the engine....(you 6.0L owners know the rest)

bummed-n-Md · August 23, 2002

the same 'normal' engine noise is in the 8.1L engines also.

beercap · August 23, 2002

Cold slap and piston flutter is nature of the beast. Some do it worse than others. It has been around GM since the early 90's. Not only GM I heard two 01 or above fords so far and 1 dodge do it louder than my 6L..Theirs did it on a warm start. Went to nascar race and was in the pits, #### them motors sound real loud, no not exhaust, but motor noise. It exist and is out there , some are loder than others.

jd hauler · August 30, 2002

I have heard about the cold knock, My truck has a about a 5 second tap in at start hot or cold, runs fine, dealer says it is the fuel rail?? any ideas??

DHuts · October 1, 2002

I've been trying to get a straight answer from Chev for over a year. They say piston slap is "not detremental" to the engine. this week I hear that they will extent warrentee (SP) to 7 yrs-100,000 miles. Anyone else hear the same?

swl2126 · October 2, 2002

There's a lot of information on this problem at:

http://www.angelfire.com/tx5/spamsite/index.html

maggot · October 2, 2002

Man this problem is real. There are some noises that can be explained as normal. My 6.oL makes 5 6 7 or more typesof pings , ticks, rattles and knocks. It has bad cold piston slap and a constant knock at all temps. The dealers have all told me it is normal for the gen3s. I can accept the cold knocks, and the fuel rail ticks. What boggles me is my lower end is getting louder and the valve train makes tons of racket, also I have a constant knock. Only answers I get is people are being too picky about the motors and knocks are now normal and no fix will ever be applied to them. I wish if it was normal it did it on the lot so you knew what you were getting. Seems like 10,000 miles is where it gets real bad. So if you ain't got 10K yet hang on buddy you are in for some good fun. I wish for straight answers, but none seems to be around anymore.

bummed-n-Md · October 3, 2002

As mentioned in an earlier post on this thread, my 8.1L knocks on startup for about 2 minutes.. On think I didn't mention was that after it warms up, then I don't really notice it myself, but a LOT of people on the side of the road look at me when I am coming down the street. The niose gets thier attention, I've seen deer take off running as I get closer, where 3 months ago, they would just watch me go by.

A new noise has also just started in the last 50 miles. I believe it is the valves but am not quite sure yet (could be the infamous fuel rail tick I've heard tell about). After the engine warms up, at idle, the engine has started 'ticking' like sticking lifters or very low oil pressure. Oil levels and pressure are fine (according to the gauage). As soon as RPMs go above idle, ticking stops (or maybe I just can't hear it anymore). The ticking at idle is loud enough to be heard inside the cab with the windows closed and over the radio.

I have also begun to notice a 'random' vibation from time to time while at idle or at speed. I feel it mostly across the floor board and in the gas peddle (seats are too 'soft' and yes, with the radio off, so I know it is not the BASS from the sound system). Having built/re-built a few engines and trannies in my youth, the best way I can describe the vibration is that it feels like two moving metal parts hit a 'dry spot' momentarilly.

I have 15,200 miles on the truck and yes, I am still going through 1 QT of oil for every 4 or 5 tanks of gas.

BDBWTE · October 10, 2002

The way is see it GM own's my truck for 100,000 miles. I have pushed this little 6 liter to death and she keeps coming back..it is acting like a 350 imo. So if it last like a 350 it will be fine...