cant pinpoint knocking noise? IMPORTANT LESSON
11-22-2009, 10:03 AM
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cant pinpoint knocking noise? IMPORTANT LESSON i recently had a problem with my 2000 ss. it was bone stock and just randomly started knocking one day when i started it to leave work. i had many people look at the car and noone could pinpoint where the noise was coming from. it sounded just like a lifter almost (but you can usually pinpoint a lifter which was odd) i took all the rockers off and pushrods out and checked everything for wear, the car has 45k miles on it so i wouldnt have thought it would have been worn. turns out it was carbon build up. the old man before me who had the car just lugged around and treated it like any other daily car. when i got the car and started messing with it and putting bolt-ons on it i must have broke some carbon loose and it was sitting on top of the piston and when it went up the piston skirt was slapping the cyl wall. to fix this problem i put a can of seafoam in the gas and sprayed water into my throttle body while running. i posted this in hopes to help someone else who may have this problem. LESSON TO LEARN : LS1's are born to be ran hard to dont worry about cops and speeding tickets and blow the damn carbon out!! 
11-22-2009, 10:25 AM
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I came across this many years ago on my dad's old Impala with a 350 motor. What realy happens is because of design of a chevy head combustion chamber only being about a halve moon looking the flat area of the head that is still above the piston when carbon build up high enough on top of the piston it starts ti hit the flat area of the cylinder head; those you get the knocking noise. My dad wouldn't believe when I told him this was what was wrong. He swore up and down it was a rod knocking. But I pointed out the oil pressure hadn't changed any. I told him to go on into town in his other car and when he came home I would have it fixed. I did the old trick of useing ATF and poured down the carb until it drowned out the engine. Let it sit for awhile to let carbon loosen up. Started the engine and it could have killed a million mosquitoes from the smoke but all kinds of pieces of carbon came flying out of the tail pipe and the knocking was gone.
11-22-2009, 10:46 AM
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atf is where its at for cleaning stuff. i had been working on cars since i was fourteen and took an automatic transmission class in tech school and my hands had never been that clean in 5 years.
11-22-2009, 07:59 PM
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I came across this many years ago on my dad's old Impala with a 350 motor. What realy happens is because of design of a chevy head combustion chamber only being about a halve moon looking the flat area of the head that is still above the piston when carbon build up high enough on top of the piston it starts ti hit the flat area of the cylinder head; those you get the knocking noise. My dad wouldn't believe when I told him this was what was wrong. He swore up and down it was a rod knocking. But I pointed out the oil pressure hadn't changed any. I told him to go on into town in his other car and when he came home I would have it fixed. I did the old trick of useing ATF and poured down the carb until it drowned out the engine. Let it sit for awhile to let carbon loosen up. Started the engine and it could have killed a million mosquitoes from the smoke but all kinds of pieces of carbon came flying out of the tail pipe and the knocking was gone.
11-22-2009, 09:52 PM
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Just after I started working at a Chevy dealer a few years back, a late model S10 4.3L truck came in the shop with a horrible knocking noise. I would have swore up and down the engine was gone, but the tech ran seafoam in it, and 30 minutes later drove it out the shop, quiet as can be.
I've never ran into this anywhere else, but its always in the back of my mind.
I've never ran into this anywhere else, but its always in the back of my mind.
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11-23-2009, 07:21 AM
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yeah about 4 out of the 5 people who looked at it said it was lifter or bent rod... thank god it wasn't!!!!!! its prob more common than most people think! thanks peppershaker for the head info!
11-23-2009, 08:53 AM
#9
This is actually very common, I've seen it alot. My ls1 sounded like a diesel all the time until i had it decarboned. You would be suprsied how fast carbon builds up in an engine if they use a little oil. That oil buring in the cylinders really adds up quick.
The gm dealers sell a 20oz can of cleaner that you add to the gas. Its actually Chevron techron the same you can buy at walmart. If you run this in your tank every 3k miles or before every oil change it will keep things clean. Its one of the few cleaners injector-carbon that really work.
The gm dealers sell a 20oz can of cleaner that you add to the gas. Its actually Chevron techron the same you can buy at walmart. If you run this in your tank every 3k miles or before every oil change it will keep things clean. Its one of the few cleaners injector-carbon that really work.
11-23-2009, 05:21 PM
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your right it wouldnt be good if you put it in the oil but into the throttle body is no big deal it will evaporate and break down the carbon as does the seafoam. but it wont hurt anything.
