08 sierra 1500 denali engine noise heeeeeelppp!
12-29-2010, 11:51 PM
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08 sierra 1500 denali engine noise heeeeeelppp!
My 08 sierra denali has 80,000 and i have noticed a noise that sounds by my ear as to be a rod bearing, based on the same sounds from older sbc engines. I have had some gm techs state that this noise could be piston slap which is common supposedly in the type engines. What do you all think about this, has anyone heard anything like this about these engines and piston slap.
The noise is very audible in the morning cold, and it will remain audible for about 5-9 mins before it quiets down, which works against all i know of a rod bearing issue where it generally gets worst when it gets warm, this noise goes away as the engine get up to operating temp. Also what type of oil pressure readings are you seing on your 6.2 engines, mine is around 40 cold, and 20 cold. My ls1 car stays around 40 all the time and my built lt1 cranks with 65-70 and settles to 55 fully warm so this seems a little low to me on the truck. I have only had the truck for almost a month, and am told that it still has factory powertrain warranty. Maybe i need a trip to the local stealership.
Your advice please!!!
Thanks in advance
The noise is very audible in the morning cold, and it will remain audible for about 5-9 mins before it quiets down, which works against all i know of a rod bearing issue where it generally gets worst when it gets warm, this noise goes away as the engine get up to operating temp. Also what type of oil pressure readings are you seing on your 6.2 engines, mine is around 40 cold, and 20 cold. My ls1 car stays around 40 all the time and my built lt1 cranks with 65-70 and settles to 55 fully warm so this seems a little low to me on the truck. I have only had the truck for almost a month, and am told that it still has factory powertrain warranty. Maybe i need a trip to the local stealership.
Your advice please!!!
Thanks in advance
12-30-2010, 10:02 PM
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Piston slap!!
Ok is this a serious fix and if so how is that, or do you mean the additional noise will drown out the slap of the piston.
So does this piston slap have any adverse affect on longevity of the engine? My oil pressure is around 20 at hot idle, and i may get up to 40 wot that i have noticed, I am going to go drive it now to see what the oil pressure does. I thought it was a bit low as well.
Has anyone had any issues with these engines and rod bearing problems. That is what it sounds like, but in an all aluminum engine these sounds travel and have diferent tones and pitches. I am a new owner for about 1 month but i want to enjoy my investment.
Has anyone had any issues with these engines and rod bearing problems. That is what it sounds like, but in an all aluminum engine these sounds travel and have diferent tones and pitches. I am a new owner for about 1 month but i want to enjoy my investment.
12-30-2010, 10:07 PM
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Is there anything i can do for piston slap, as i have a friend with a 6.2 gmc and his has about 72000 miles and it does not make this scary noise when he starts up on cold starts.
Just a thought, what causes this, is the engine wearing internally.
Thank you to all of you all!
Just a thought, what causes this, is the engine wearing internally.
Thank you to all of you all!
12-30-2010, 10:39 PM
#6
Not getting into the actual condition of your particular engine, as diagnosing something like this via the e-net is futile, but as far as pistons and engine noise is concerned>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>
As these newer motors build up mileage the coating on the piston skirts can and will wear off, creating more piston to cylinder wall clearance and in turn creating additional engine noise the coating was originally designed to help eliminate.
Example of a 6.0L:
Piston-to-Bore Clearance – LQ9 Production: 0.00094-0.00098 in
Piston-to-Bore Clearance – LQ9 Service Limit (skirt coating worn off): 0.00094-0.0031 in
From the example, you can see how much acceptable clearance there is once the coating on the skirts is worn away.
As these newer motors build up mileage the coating on the piston skirts can and will wear off, creating more piston to cylinder wall clearance and in turn creating additional engine noise the coating was originally designed to help eliminate.
Example of a 6.0L:
Piston-to-Bore Clearance – LQ9 Production: 0.00094-0.00098 in
Piston-to-Bore Clearance – LQ9 Service Limit (skirt coating worn off): 0.00094-0.0031 in
From the example, you can see how much acceptable clearance there is once the coating on the skirts is worn away.
Last edited by 1Bear; 12-30-2010 at 11:16 PM.
12-31-2010, 01:13 AM
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not getting into the actual condition of your particular engine, as diagnosing something like this via the e-net is futile, but as far as pistons and engine noise is concerned>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>
as these newer motors build up mileage the coating on the piston skirts can and will wear off, creating more piston to cylinder wall clearance and in turn creating additional engine noise the coating was originally designed to help eliminate.
Example of a 6.0l:
Piston-to-bore clearance – lq9 production: 0.00094-0.00098 in
piston-to-bore clearance – lq9 service limit (skirt coating worn off): 0.00094-0.0031 in
from the example, you can see how much acceptable clearance there is once the coating on the skirts is worn away.
as these newer motors build up mileage the coating on the piston skirts can and will wear off, creating more piston to cylinder wall clearance and in turn creating additional engine noise the coating was originally designed to help eliminate.
Example of a 6.0l:
Piston-to-bore clearance – lq9 production: 0.00094-0.00098 in
piston-to-bore clearance – lq9 service limit (skirt coating worn off): 0.00094-0.0031 in
from the example, you can see how much acceptable clearance there is once the coating on the skirts is worn away.
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12-31-2010, 10:49 AM
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Take it to the dealership and see what they can do for you. I have an inlaw that is a GM tech and he's told me that they get the 6.0's in with piston slap, if the guy complains enough they'll swap it out. If there going to take the time to measure your piston to bore clearance they'll just put a new engine in.
Good Luck
Good Luck
12-31-2010, 05:06 PM
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Took a trip to the local dealership!
Ok I went to my local dealership and they suggested that i take the truck and perform an oil change on it first and see if there is any change in the oil pressure and cold startup sound. THey suggested that at hot idle 20-25# may not be an issue, I did try reving the engine in park and the most I get is about 40# or so, I have yet to see 60# of oil pressure. 
They think it may be a choice of oil maybe issue, so I am gonna try this out maybe tommorrow to see what happens.
I think I am gonna try a set of plugs as well, to see if I get rid of my miss as well.
WISH ME LUCK
They think it may be a choice of oil maybe issue, so I am gonna try this out maybe tommorrow to see what happens.
I think I am gonna try a set of plugs as well, to see if I get rid of my miss as well.
WISH ME LUCK