? for 4.8 vortec owners...

[Chevyc10]

 Hello all, got a question for all you 4.8 owners.   Are your motors making a tapping sound, similar to what a lifter would sound like?  My 01' has developed a sound like that.  The last time I took the truck to the dealer (different problem) I was told " they all do that " excuse.  Just wanted to know if this is something I should just put up with.  The dealer is a long distance away, especially for a drop off.  Anyway, lets hear it...

Thanks, Jake

[Roofer]

I have the same problem with my '00 5.3l. There are alot of 5.3's and 4.8's with this problem. I was told the same at the dealer, but they also said a fix is in the works. I read on another forum to call this # 1-800-222-1020, and have your vin # on hand. Some say different things, but I just hope GM gets on the ball and gets something done. Make sure you bring it to the dealer and that they store your complaint in their computer. That way, if warranty runs out, you have something to go back on.

 

[Stepside Z]

My 99 4.8 did not do it 36k miles and my 01 4.8 does not do it 1800 miles. How many miles do you guys have on your trucks and does the noise go away when it warms up?

(Edited by Stepside Z at 11:36 pm on July 17, 2001)

[ChrisG]

Howdy All,

My 8.1 has done it since day one. It reminds me of the sound of the old solid tappets used to make in the 60's but louder and goes away when the engine is warm. I'm about to make a trip to the dealer (wish me luck) to find out about it. I just changed the oil to 10W30 full synthetic thinkin' maybe..........no luck still tickin' I'll let ya'll know what I find. I've got just under 6K on her.

CG

P.S. Are the lifters solid or hydraulic roller?

(Edited by ChrisG at 3:19 am on July 18, 2001)

[tbensor]

It almost sounds like noisy injectors.  TAP,TAP,TAP.....

[Roofer]

I have 40K on mine and it has been ticking since maybe 15K ago. It comes and goes, but it doesn't goaway when warmed up. I drive all the way to a job (20-30 miles) and it still ticks about 80% of the time.

Also, my buddies '00 ZR2 makes the same noise but much quieter.

[Chevyc10]

 I only got 3600 miles on it!  I guess I will go ahead and at least lodge a complaint!  Thanks folks...

Jake

[chevy4x4trucks]

mine has done it, or at least i've noticed, for the last few thousand miles.  There's about 13,000 on the truck now and i can hear it when the windows down and the sound reflects off the building or if I'm outside the truck when it's idling.  It's not that rapid, almost one a second.

[Chevyc10]

 Well I took mine in and of course they could barely hear it.  They even drove another one around to compare and claimed that it was doing it to.  It wasn't, matter of fact, you could hear mine over the other.  Either way they said that they can't do anything about it unless it is more prevelent.  That Sucks!!! I am sick of hearing it.  You would think that an engineer could "engineer" a better motor.  One mechanic said that it was just a little "piston slap"!!!!   Sure, just a little piston slap.  NOT ON A BRAND NEW MOTOR WITH 5,000 MILES ON IT BY GOD!!!   I hope someone at GM views this site...

  Guess I'll just sell it and get the 5.3...

[jimbello]

Not for nuthin guys but Chevy engins have been notorious for noisy intake manafolds. Kind of a tap,tap,tap.....or even a chuga, chuga, chuga noise. I noticed this way back in the '70s.

Could be just that too.

[oxidizr]

Actually the noise you are describing is refered to as "cold knock." It is an event that occurs in loose tollerance motors such as the LM7. It isn't necessary bad moreover it basically annoying. However due to the overwhelming reports of these sounds to GM they made a revision in 2001+ 4.8,5.3&6.0 motors in which they tightened up the main tolerances. For those of you 5.3L 2001+ owners, haven't you ever noticed that you can peg your oil pressure gauge at normal operating temp at WOT with only 3500 R's on the tach?...This is why.

[CapnDean]

My 2001 4.8 does not make the noise. (9K miles).  I have read several reports on the "cold knock" problem with these engines.  I hope mine doesn't start.  

I know the feeling...maybe it doesn't hurt anything, but common sense has always told all of us that a knock in a motor is NOT good.   In fact a local engine rebuilder was notorious for having his engines knock...The joke was as follows:

"Knock Knock"; "Who's There?"  "Kenny Young".

No offense intended to Kenny though...I had one of his engines that ran a long time no prob.

 

[Badger]

My 01 has 1800 miles and no knock or ping from the enigne.

[dennym]

Hello all, got a question for all you 4.8 owners. Are your motors making a tapping sound, similar to what a lifter would sound like? My 01' has developed a sound like that. The last time I took the truck to the dealer (different problem) I was told " they all do that " excuse. Just wanted to know if this is something I should just put up with. The dealer is a long distance away, especially for a drop off. Anyway, lets hear it...Thanks, Jake

[dennym]

Hello all, got a question for all you 4.8 owners. Are your motors making a tapping sound, similar to what a lifter would sound like? My 01' has developed a sound like that. The last time I took the truck to the dealer (different problem) I was told " they all do that " excuse. Just wanted to know if this is something I should just put up with. The dealer is a long distance away, especially for a drop off. Anyway, lets hear it...Thanks, Jake

 

I've got one with 200000 mile on it. I do not remember when the noise started (awhile ago). last month I was checking looking underthe hood and noticed one of the exhaust manifold bolts was missing its head. The passanger side has tow heads missing. I have an exhaust leak from the drivers side. After the thing warms up the exhaust manifold heats up and warps back into shape (no more leak). One of the guys I work with has had the same problem. He took it to the dealer to ger repaired, it was about $1000.00 cause they broke the stud off flush with the head and ahd to remove the head to properly bore it out:(