Intermittent engine knock...
Thread Starter
Teching In
Joined: May 2005
Posts: 48
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Intermittent engine knock... Ok Gang,
In addition to my Z, the wife has a 2000 impala with a 3.4L V6. It leaks coolant around the intake, which is common, and I got ready to tear it down when all of a sudden, we heard a knocking sound from inside the engine. Its not the top valve train, and it will knock a few times when first started, then randomly every few seconds. I revved the engine and it did that fine without knocking, but when the rpm's were dropping off, it would knock. I used the old stethoscope tool and it sounded like the middle of the engine.
I do not believe it is a rod because it is not continually knocking, nor has it come out of the block. My thoughts are a lifter going bad. Now that I have the intake off, I checked and they all have close to the same tension on the pushrods, and nothing looks damaged, or obvious. Before I pull the lifters out, can someone tell me how to check them, because they are $23.00 each and I don't want to have to replace all if I don't have to.
Also, any other ideas what could cause the knock or other things I should look for? I know this is an LS1 forum, but you guys have always helped in the past.....
Jim
In addition to my Z, the wife has a 2000 impala with a 3.4L V6. It leaks coolant around the intake, which is common, and I got ready to tear it down when all of a sudden, we heard a knocking sound from inside the engine. Its not the top valve train, and it will knock a few times when first started, then randomly every few seconds. I revved the engine and it did that fine without knocking, but when the rpm's were dropping off, it would knock. I used the old stethoscope tool and it sounded like the middle of the engine.
I do not believe it is a rod because it is not continually knocking, nor has it come out of the block. My thoughts are a lifter going bad. Now that I have the intake off, I checked and they all have close to the same tension on the pushrods, and nothing looks damaged, or obvious. Before I pull the lifters out, can someone tell me how to check them, because they are $23.00 each and I don't want to have to replace all if I don't have to.
Also, any other ideas what could cause the knock or other things I should look for? I know this is an LS1 forum, but you guys have always helped in the past.....
Jim
Thread Starter
Teching In
Joined: May 2005
Posts: 48
Likes: 0
I wish it was the case.........its the wifes V6....3.4 and it knocks......but not a piston knock....does anyone know how to test the lifters to see if they are bad....I like the radio turned up theory...but the wife would shoot me if I put it back together and did not fix it right........lol
