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Slight knock during acceleration?

12K views 18 replies 7 participants last post by  darkman 
#1 ·
Ok fellas, i have the ls2 motor, 70k miles and it makes a Knocking noise only when accelerating. Its a deep knock kind of a rod knock but alot quieter, the windows have to be rolled up and radio off in order to hear it. It sounds like its coming directly below the center console area. Any ideas where to begin my diagnosis? Thanks
 
#4 ·
Sorry to hear that, 06BlackV. We recommend consulting with your dealership for an initial diagnosis, but if you're more of a DIYer, I can appreciate that! Please feel free to send me a private message if you ever want me to investigate any questions you may have while going through the process. I can always double check my resources on your behalf!

Have a great weekend,

Katie
Cadillac Customer Service
 
#7 ·
06 I swore I had a knock (100k) but tell me this, does it get less pronounced after two to three minutes? If so, I'm almost certain it's cold factory headers. This engine took some getting used to. I've heard some refer to our top ends as sewing machines which made me laugh. But it was hard trying to diagnose that sound with the injectors and coil pack noise going off. Now if I run 89 and let er rip, I will sometimes hear valve knocking/flutter sounds and that is very discernible. If I put 93 and some octane boost in, it wont happen. I'm not crazy about the engine sound, but that's why I stomp on the gas. To hear the exhaust. Plus a K&N CAI with the flap removed will create a nice loud sucking whistling sound to mask it lol.
 
#9 ·
Oh ok. Did you by chance do a blackstone oil analysis yet? I'm not sure if that would show valve train wear. That's one example of non invasive trouble shooting. I have to do mine again to get baseline. I only had a few ppm above normal on cylinder wall metal and they said that was indicative of "spirited driving" nyuk nyuk.

Mike
 
#15 ·
Older water pumps used to "knock" when the bearing was going out. ??? Have you used a stethoscope?
Edit: I reread the first post. If its coming from the console area could be the throw out bearing. I know you said out was replaced but could be that or a finger on the pressure plate.
 
#16 ·
I was thinking the throw out bearing as well, im afraid when they installed my clutch , they didnt do something right or damaged something in the process:/ the noise is very mild i didnt really notice it till about a week ago because i always have music playing or windows down so i wasnt able to notice the noise.
 
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