Need Advice: 2009 5.3 Silverado engine knock question
STech
03-16-2010, 11:54 AM
I have a 2009 5.3 Silverado Z71, Since new I have a weird noise that I cant pin point exactly where it comes from.
When starting the truck after it has sit for 1 to 2 hours I get a semi loud knocking sound kind of like piston slap but just a little different. It lasts for approx 2 to 3 minutes. It is not there at all when starting from cold in the morning, or sitting for a long period of time, only after its been driven and then sitting for an hour or so. The dealership is stumped, they have heard it a few times now but just cant pin point it.
I seem to pick it up with a stethoscope the best at the oil pump or on the side of the block at the #1 cylinder area. But again it doesn't do it on first start in the AM.
Anyone ever hear of this or have any ideas.
When starting the truck after it has sit for 1 to 2 hours I get a semi loud knocking sound kind of like piston slap but just a little different. It lasts for approx 2 to 3 minutes. It is not there at all when starting from cold in the morning, or sitting for a long period of time, only after its been driven and then sitting for an hour or so. The dealership is stumped, they have heard it a few times now but just cant pin point it.
I seem to pick it up with a stethoscope the best at the oil pump or on the side of the block at the #1 cylinder area. But again it doesn't do it on first start in the AM.
Anyone ever hear of this or have any ideas.
kahjdh
03-16-2010, 05:50 PM
Wow, interesting. Is it a gen 4 motor?
j cAT
03-16-2010, 07:58 PM
I have a 2009 5.3 Silverado Z71, Since new I have a weird noise that I cant pin point exactly where it comes from.
When starting the truck after it has sit for 1 to 2 hours I get a semi loud knocking sound kind of like piston slap but just a little different. It lasts for approx 2 to 3 minutes. It is not there at all when starting from cold in the morning, or sitting for a long period of time, only after its been driven and then sitting for an hour or so. The dealership is stumped, they have heard it a few times now but just cant pin point it.
I seem to pick it up with a stethoscope the best at the oil pump or on the side of the block at the #1 cylinder area. But again it doesn't do it on first start in the AM.
Anyone ever hear of this or have any ideas.
I would demand they send the engine oil out to be tested for metals....could be main bearings or piston issues ..this is typical of a noise that is temperature sensitive ..
also oil pressures what are you getting ?
When starting the truck after it has sit for 1 to 2 hours I get a semi loud knocking sound kind of like piston slap but just a little different. It lasts for approx 2 to 3 minutes. It is not there at all when starting from cold in the morning, or sitting for a long period of time, only after its been driven and then sitting for an hour or so. The dealership is stumped, they have heard it a few times now but just cant pin point it.
I seem to pick it up with a stethoscope the best at the oil pump or on the side of the block at the #1 cylinder area. But again it doesn't do it on first start in the AM.
Anyone ever hear of this or have any ideas.
I would demand they send the engine oil out to be tested for metals....could be main bearings or piston issues ..this is typical of a noise that is temperature sensitive ..
also oil pressures what are you getting ?
kahjdh
03-17-2010, 05:14 PM
Gen 4 meaning MDS or DOD?
Retiredgunner
03-19-2010, 11:02 PM
Isn't this noise called piston slap?
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