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Knock Or Tick When Cold

outlaw1

By outlaw1
in Ask A GM Technician

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outlaw1 Enthusiast

outlaw1

Posted
Posted

I have a 2001 1500 with a 4.8L Automatic. 100,000 miles. Bought truck new. no mods. Oil change evey 3-4k syn.

 

When I first start it When the weater is cold in the mourning I can hear a knocking or loud tick. Havent been able to locate the source. When the engine warms it is gone. On a warm mourning this dosent happen. Oil filter and oil has been changed several times. AC filter Mobil 1 10W30. Also this is the second winter I have heard this.

 

Any ideas.

pwall Senior Enthusiast

pwall

Posted
Posted

Welcome to GM....most likely that is piston slap and is considered 'normal'. :D

outlaw1 Enthusiast

outlaw1

Posted
  • Author
Posted

Thanks for the reply. I have thought about the piston slap. But this motor was as quite as a church mouse up until last winter. Dont know how I would have reduced the piston to wall clearance.

 

Normal Huh. Who said that it is normal?

pwall Senior Enthusiast

pwall

Posted
Posted

GM says it's normal.....of course they do. They would have to fix a lot of motors.

chevy6490 Enthusiast

chevy6490

Posted
Posted

It is instability of the piston in the chamber, like pwall said, gm consideres this normal and no problems arise from it. Mine is terribly loud for a few minutes then its fine, havn't had any engine problems result from it.

 

Zach

outlaw1 Enthusiast

outlaw1

Posted
  • Author
Posted

I am not new to there normal knocks or noises. I was awareded this truck in 2002 on BBB claim on so called normal. I would advise you if you have low miles to make a claim.

jhm Senior Enthusiast

jhm

Posted
Posted
I have a 2001 1500 with a 4.8L Automatic. 100,000 miles. Bought truck new. no mods. Oil change evey 3-4k syn.

 

When I first start it When the weater is cold in the mourning I can hear a knocking or loud tick. Havent been able to locate the source. When the engine warms it is gone. On a warm mourning this dosent happen. Oil filter and oil has been changed several times. AC filter Mobil 1 10W30. Also this is the second winter I have heard this.

 

Any ideas.

I have the same truck/engine/oil changed regularly. I only have 60k on it but last winter the cold start knock reared it's ugly head. Now I get it even in the fall if temps drop into the 40's. They claim it does no damage, I will decide for myself depending on what happens down the road. Once bitten....

outlaw1 Enthusiast

outlaw1

Posted
  • Author
Posted

I am really not satsified this is a piston slap problem. It clears up so fast on warm up. can't really tell. Almost sounds like a loud lifter.

  • 2 months later...
KB06YUKONXL Enthusiast

KB06YUKONXL

Posted
Posted

I am posting on this thread because I have this on my 2006 Denali 6.0L . Took it to the dealer once at 24000 miles and got the "normal" response. Took it back at 32000 when the knocking lasted 3-5 minutes and still under warranty. The dealer decarboned the throttle body and removed the spark plugs and soaked the pistons with top end cleaner and the knock is gone. I requested an extended warranty and GM sent me a letter extending my 3/36000 warranty on the engine to 6years/100,000 miles. So I am thankful that GM has stood by their product. As for this dealer, they will get ALL my business in the future because they have treated me very well.

minibike132 Senior Enthusiast

minibike132

Posted
Posted

You learn something new every day. The issue never makes it back to us. You all get the normal speech before it gets back to me. I have never really been satisfied with the "it doesn't cause any problems" theory but after 10 years I can't really prove it wrong. But I do have a real good customer that comes back and talks for a bit when he comes in and he's got the knock. I'm going to try a good top engine clean next time he's in and see what happens.

  • 2 months later...

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