Jump to content

Engine Knock

seadoons

Do you have it and when?  

701 members have voted

You do not have permission to vote in this poll, or see the poll results. Please sign in or register to vote in this poll.

Recommended Posts

Sniper Enthusiast

Sniper

Posted
Posted
2000 sierra 5.3 with 140,000 knocks on startup when the engine is cold.after warms up no knocky.

 

Wow! You actually counted the knocks? Just kidding. I read that and couldn't resist... :rolleyes:

  • 1 month later...
  • Replies 184
  • Created
  • Last Reply
mizzoueng Enthusiast

mizzoueng

Posted
Posted
To clarify the question about engine knock please note what engine you have.

 

The 5.7L 350 Chevrolets are known to knock on start up. # 1 Main Bearing is getting loose.

You hear a deep knock that hits only a few times and quickly gets softer then leaves as oil is pumped into the main bearing.

Usually above 80,000 miles. No need to panic unless it gets worse. Will run many thousands of miles after first hearing it.

Will be louder the longer the vehicle is parked and maybe not there at all on a short term restart. If it does not get worse I would not worry about fixing it till you have a reason to open up the engine for something else. I put new main bearings in my 1995 Suburban to eliminate this noise at 155,000 miles. Lot of work and you risk causing other issues when you open an old engine and don't do a complete overhaul.

A friend bought this from me and it is still quiet and strong at 190,000.

 

The newer family, 4.8L, 5.3L and 6.0L suffer piston slap on start up. Not all but some do it.

Should only hear this on cold start. The block must be cold. Pistons will rattle till temperature on the piston makes it grow a little and then they are quiet. This one can start when the truck is brand new and do it till you retire the rig.

This noise should go away in 10-15 seconds. If it is longer or does it in all conditions it may be another issue.

Piston slap is worse in cold weather and better in warm weather. It won't shorten the life of your engine.

GM is running short skirt pistons in these engines, just like racers have always done. ( last 20 years anyhow ).

It is hard to run a quiet short skirt piston in a working engine but GM has done it quite well.

They help with Power and Mileage, negative is noise on start up.

Some of you may remember this noise from building high power engines with Forged Pistons in the 60s through the 90's.

The Forged pistons used to need more clearance and made noise on start up.

Have not seen any bearing failures on this family of engines unless they are not maintained.

My 2001 Denali 6.0L had the noise from new till sold with 89,000 miles, I hated the noise. My 2002 Tahoe 5.3L does not have it yet at 80,000 miles, luck of the draw.

 

Its been really cold here lately, i noticed a knock at startup but it went away. This is the answer I was looking for.

GasHog369 Senior Enthusiast

GasHog369

Posted
Posted

mine knocked a little on startup , but ever since i switched to royal purple it has disappeared.

04z71steve Enthusiast

04z71steve

Posted
Posted
mine knocked a little on startup , but ever since i switched to royal purple it has disappeared.

 

i'm switching to royal purple soon! i'll let u know if i see the same change!

99xjsport06 Enthusiast

99xjsport06

Posted
Posted

2004 Silverado 4x4

5.3L V8

Used to knock last winter every cold start up...no matter if it sat over night, or sat for 4 hours. Knocking lasted approx. 5-15 minutes depending on how long it had sat. Oil consumption at the time was approx 1-1.5 quarts per 3K.

 

As of this winter, no more knocking. Oil consumption has increased however to 3-3.5 quarts per 3k.

 

Mileage on engine at the moment is 112K, all highway.

 

Still blows out a fair amount of oil on a cold start up if parked facing up hill.

troopythetrooper New Member

troopythetrooper

Posted
Posted

I just purchased a 2002 Chevrolet Suburban 8.1 66k miles. What ever oil was in it originally it made NO noises at all. I then switched to Rotella 5w40 synthetic and it had bad Piston Slap and a little Rod knock when 25 degrees or below.

 

Switched to dino 5w30 and AC delco filter no rod knock but still does the piston slap thing when it sits for a few hours/not as bad. It also does it very lightly as it comes down from idle.

 

I wish I knew what exactely what was in it. Besides all this its seems to be a great truck, I think I still liked my 93 with the Tonawanda 454 better. Oh well.

  • 2 weeks later...
punmax Senior Enthusiast

punmax

Posted
Posted

Can somebody explain to me what you feel when you get knock/pinging? My engine when at idle will vibrate a lot... I will mention in it next oil change.

d3athsong Enthusiast

d3athsong

Posted
Posted
Can somebody explain to me what you feel when you get knock/pinging? My engine when at idle will vibrate a lot... I will mention in it next oil change.

 

Youll hear it if its knocking or pinging

  • 1 month later...
dk1125 Enthusiast

dk1125

Posted
Posted

I had a 2000 sierra with 6.0 and 162,000 miles Sounded like a diesael on start up, mostly when it was cold outside. But it ran great only repair done to the engine was I relaced knock sensors 1&2 as per the emc code i was getting. I traded it off in dec.07 for an 08 sierra, the only reason for getting rid of it was I needed the ext. cab for the family. BEST VEHICLE I EVER HAD!!! P.S. I realy miss that truck

ajcain79 Enthusiast

ajcain79

Posted
Posted

2007NBS -6.0 - 6,200mi.

 

I have not been infected with the knock like some of the more promiscuous folks on this site.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • newdude
      2027 3.0 l Duramax

      By newdude · Posted

      Thrust bearing is a very small window.  But nice try.   Turbo oil filter?  Haven't seen any failures.  Change your oil more frequently.  Use a better oil than the factory oil.  
    • newdude
      2026 sierra bad brake controller

      By newdude · Posted

      There is a p/n called out in the one PI that GM has.  Curt 57003 inline load adapter that is used for LED trailers that are having trouble with these newer trucks.  No cutting, no splicing, etc.  GM did update the lighting module around 2023 to better pick up trailers with LED lighting, but it still can happen.     Here's the link to the Curt site for it - 7-Way RV Blade LED Electrical Adapter (Not a Wiring Extension) SKU #57003 by CURT   The PI I am referencing - MC-10208985-9999.pdf   Its not just a GM deal either.  Newer Fords and Rams have this same problem.       In another PI, they recommend that the trailer has a Pollock brand 7 way on it as that is who makes the truck sides for the OEMs.  GM is also big on making sure the trailer is trouble free.  So no wiring issues, all lights are functional, better quality 7 way plug, etc.     The other PI I am referencing - MC-10178359-9999.pdf   The model year range is older but it is the current PI for 2014-2026.  It calls out the Pollock RV HD 7 way they recommend.  
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      That's part of the problem...the EGR has already been replaced, and I've already had the complete intake assembly removed, and the EGR passages were clear at that time. That leaves wiring, PCM, or another variable that I wasn't expecting. Best I can tell, it's not wiring or the PCM, so I'm grasping for straws.   The PCM uses the MAP reading to confirm the requisite loss of vacuum in the manifold when the EGR activates. Since that's vacuum related, it involves a lot of other systems which could play a role.   The overall diagnosis has to be considered too. The fuel lines in the intake had rubbed through and were dumping fuel into the intake, drowning the cylinders in fuel, and putting raw fuel into the sump and cat converter. The fuel system has been fixed but the complete path of damage may not be. If the cat was damaged and melted the internals, it could be partially obstructed and also playing into the EGR issue.   I'm retracing my steps; trying to go back to thinking thinking Horses not Zebras based on the clues I've been given. These engines aren't *that* complex.   Could it be, now that the truck is running well, that carbon and crud from being run with the fuel system in disarray is now dislodging and clogged my clean EGR passages where I can't see?  That's what the code is actually saying. The flow is restricted, dummy. Retrace step 1.   I may just need to remove the lower intake again. Before I do that I'm going to try removing the EGR and running the engine for a few seconds to see if it will blow anything lodged in the egr passages out through the open ports.     That's been helpful in the past. For the spider injector, there's no guarantee I'll get a working one. The spider I have seems fine now that the high pressure fuel line isn't making an early delivery via large hole. SO at least I'm not marooned and looking for one of those.   Row52 (dot com) is also a good one for watching for vehicles at local yards.  
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Disassembly may be Required!   Every blender makes claims but do  you ponder those claims? What was really said? Was it true?  Motive for saying it? What does in infer?  Is that inference true?    Let's do one.    Claim: Made from shear stable base oils.    What was said: Base Oils are shear proof.   Was it true: Yes.  ALL base oils are Newtonian.    Motive / Inference: To imply the fully formulated product is Shear Proof.    Is the Inference true?: Most fully formulated multigrade oils contain Viscosity Modifiers or VM's, sometimes called VII or Viscosity Index Improvers. There are four types. One is in fact shear proof but it also has a bad effect on extreme cold flow and is restricted to use in specialty oils. A second has limited shear called a 0-5 SSI polymer. Meaning its shear is limited to a range of zero to five percent as reported by the ASTM D6278 Shear Stability Index test. A few high end oils, like Torco SR-5, use them and brag about it profusely. Actually all that use it point it out. The last two shear dramatically and are often marketed as a 'feature' of the product aiding the oil to meet fuel standard requirements of ever stricter rules. One shears more than 5% and the other up to 20%. As you make guess, cost is directly linked to shear down and as such the majority of oils use the cheapest organic polymers sold to make grade and pass stringent tests.    PPD's or Pour Point Depressants also shear a bit, only a few percent and hide inside the 0-5 SSI capabilities.    The blender knows he can not out engineer Stribeck. Physics is not a suggestion. But he can wordcraft the unsuspecting toward believing a false claims INFERENCE. This is LEGAL. It is COMMON, and it is EFFECTIVE.         
    • Jsdirt
      2006 Silverado HVAC sensor location in dashboard

      By Jsdirt · Posted

      I don't recall ever dealing with one on an '06 and back. It may not even exist on that. I can't remember for sure.   Any kind of ice in or after the evaporator is normally due to low charge with both a clutch-cycling orifice tube system, and a TXV system.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...