Engine Knock

Kamyoon · November 18, 2003

2000 GMC Sierra 4.8L Z71....Darn thing sounds like diesel engine...It used to be only at start up and would go away afterwards (30K miles). Now at 60K it is all the time. At high rev it just gets blended in with other engine noises, but if you rev it in the garage, you definitely can hear it.

Stealership said yes there is a noise, but not their problem. GM says it wont effect anything other than my sanity.

Took it to a an independent auto repair shop (Conrad's in Ohio), and he said yes there is and it is hard to believe that it won't have any effect on the engine. Any metal to metal contact that makes this noise, will eventually wear the contact surface. Suggested to call dealer, write district manager, write GM, write local congressman, and check into Lemon laws. Diagnostics show no issues at this time.

Cleveland Plain Dealer and Detroit Press had an article 11-17-03 on people sueing GM for the noise issue. Also on radio.

Bob G. · November 18, 2003

2002 1500HD/6.0L/27,242 miles

Has cold start knock since day 1. Goes away after 20 - 30 seconds. Will usually go away sooner if I put it in "drive".

Bob G.

LogixRat · November 18, 2003

2000 GMC Sierra 4.8L Z71....Darn thing sounds like diesel engine...It used to be only at start up and would go away afterwards (30K miles). Now at 60K it is all the time. At high rev it just gets blended in with other engine noises, but if you rev it in the garage, you definitely can hear it.

Stealership said yes there is a noise, but not their problem. GM says it wont effect anything other than my sanity.

Took it to a an independent auto repair shop (Conrad's in Ohio), and he said yes there is and it is hard to believe that it won't have any effect on the engine. Any metal to metal contact that makes this noise, will eventually wear the contact surface. Suggested to call dealer, write district manager, write GM, write local congressman, and check into Lemon laws. Diagnostics show no issues at this time.

Cleveland Plain Dealer and Detroit Press had an article 11-17-03 on people sueing GM for the noise issue. Also on radio.

Have you checked out PistonSlap.com yet? If not give it a glance. There is alot of info on that site that may be beneficial in pursuing GM, if you decide to go that route. I hate the fact that GM customers have to turn to legal resolutions, but sometimes it takes a loud squeak or series of squeaks before anything gets oiled.

Squeak away!!

GM GIMP · November 19, 2003

'02, 1500HD 6.0 knocks at startup but quits after about 10-15 seconds.

jhm · November 19, 2003

34k on 4.8l, no knock...knock on wood!

JayMan · November 20, 2003

When new, which was end of August 2000, would knock-knock for the first 10-20 secs. At 1600 km (1000 miles) changed the oil to Mobil 1 0W-30 and a Mobil 1 filter. No more knock.

March 2001, changed to Mobil 1 10W-30 and a Purolator filter. BAD knock. Removed the oil filter and put on a dealer AC Delco PF-59. No more knock.

Now has 57990 km (36033) miles, no knocks since. Oil consumption from 1 qt / 4200 miles to 1 qt/7300 miles. That's good, right?

kdm101 · November 20, 2003

When new, which was end of August 2000, would knock-knock for the first 10-20 secs. At 1600 km (1000 miles) changed the oil to Mobil 1 0W-30 and a Mobil 1 filter. No more knock.

March 2001, changed to Mobil 1 10W-30 and a Purolator filter. BAD knock. Removed the oil filter and put on a dealer AC Delco PF-59. No more knock.

'99 4.8L rado

I too use nothing but Mobil-1 oil and filters (got myself a multi-year supply when all the local K-marts closed down) with only 2 or 3 exceptions since I bought it.

Mine rarely ever made any noises at startup until this fall. Now, every morning I'll get the 10-15 seconds of valve/lifter noises until oil pressure builds. I'll just keep my fingers crossed that it doesn't get any worse than that. I only just ticked over 40K this morning on my way to work as I hardly drove it my first two years.

PS: For whomever had mentioned about whether it's Canadian or US made vehicles, for the record, mine's from Canada. Eh!

JayMan · November 20, 2003

Not too sure if the valvetrain noise is really a problem. My first new truck, a 1984 Ford F-150, made a clatter when first started, and made a tick-tick ALL the time. At 5000km / 3000mi changed to Amsoil 10W-40. At 120,000km / 74564mi the noise got worse.

I took off the valvecovers and retorqued the rocker arm bolts to the service manual spec. Some bolts were LOOSE!

Most of the noise went away. FYI on the Ford 302 you adjust the valvetrain by using different length pushrods. Ever seen a Ford newbie take off the heads for some reason or another, throw all the pushrods into a box, then reassemble at random? HA! You're pooched!

My 302 still runs fine at 486,000km / 301986mi, though I only use it off road for getting firewood. Yeah, the tick-tick and clatter-clatter is still there on startup.

US vs Canada trucks: My Ford was assembled in Oshawa, Canada, my GMC was assembled in Indiana.

Grover · November 22, 2003

I have the engine knock in my '00 Yukon SLT with the 5.3L

COZWV · November 22, 2003

Mine knocks horribly on cold mornings and knocks slightly all the time. 2000 6.0 liter.

JayMan · November 22, 2003

My dealer - they're actually quite good and easy to deal with - claims they've had some bad 4.8/5.3/6.0 Vortec's, though only a handful. To prove a point, at -30 F the service manager went outside with me and started up a used 2000 5.3.

KNOCK KNOCK KNOCK they ordered a new motor.

He then started up a used 2002 5.3. Quiet and smooth.

When you bring your truck in for the complimentary 2500km initial service, they fill the motor with Mobil 1 5W-30 or Mobil 1 0W-30, depending on time of year. They also strongly recommend using Mobil 1 in the motor.

Some posts suggest using a good synthetic does NOT help. It helped me. I would suggest if oil consumption isn't more than 1 qt per 4000 miles, the motor is tight and there shouldn't be any problems.

You'd think they would look into this while testing those motors, right??

BlackSilver · November 22, 2003

2001 5.3L 60,000 miles -- whisper quiet.

2003 6.6L 25,000 miles -- it's supposed to sound like that.

chevroletmb · November 23, 2003

just because your vehicle was assembled in canada or the usa or mexico doesn't mean the whole car is built there. a vehicle can be assembled in canada with an american built motor and a transmission built in france for example

(i'm not saying they're made in france but you get the idea)

samuriarte · November 23, 2003

Mine started at 10,000 miles. piston slap on cold start only. Have had supercharger on it for 7 months now. No internal probs

MrQuadrasteer · November 23, 2003

Okay, I know there's a million threads on it.... but, isn't rumored to have been eliminated in 03 and newer motors ?? If so- what'd they do to fix it ????

Also, saw some sweet pre-lubers last night. Would that help in keeping the csk at bay, or is it more just in the design of the piston skirts ??

FWIW, at 3800 miles (knocks on wood), did it once for about 5 seconds, never again. (I read where someone had csk, in an unrelated incident he had punched the throttle to the floor for a good while, blew carbon smoke (??), but hasn't knocked since, lending some support the carbon-based arguements...) Since I punch it often........ I should be good !!!!!

I'll leave the poor horse alone now.....