Knocking noise...Valves??

[09Duramax]

My pickup started making a knocking noise this evening. I shut it off when I got to walmart after I let it cool down and when i got back out, started it up and drove home I noticed a kncoking noise. It only does it at idle when you first start it up and slowly fades away, but hwen you rev it up anywhere above idle it knocks. It it coming from the top of the motor as far as I could hear. I don't run my H&S on anything but stock and its only been deleted about 500 miles, only 4,700 miles on the pickup. Any experience with this? it's not the typewriter noise, I've got that too.

[09Duramax]

........bump

[Hunter69]

Ok, this is going to sound bad, but it worked for me, I had the same issue, u can go to ways, add another muffler( total2) or find a diesel cat from a 6.4 or 6.0 and install it before the muffler, during idle ur engine is not spooling the turbo and the valves are just flapping without any pressure, if u keep this up you will burn your valves, mine has 7k miles now with no problems ,

[09Duramax]

I put it all back to stock and it was still knocking just as loud...So it's at the dealer now.

[09Duramax]

Dealer replaced #7 injector and HPFP...didn't help, so they told me to drive it until it scattered.

[csdwarf11]

haha! run it still it scatters? run it hard, make it happen! they will warranty it right?

[wilsonw2]

Originally Posted by Hunter69

Ok, this is going to sound bad, but it worked for me, I had the same issue, u can go to ways, add another muffler( total2) or find a diesel cat from a 6.4 or 6.0 and install it before the muffler, during idle ur engine is not spooling the turbo and the valves are just flapping without any pressure, if u keep this up you will burn your valves, mine has 7k miles now with no problems ,

Hmmmm. So ur saying idling will burn ur valves? I'm not challenging ur intelligence but I don't believe that. Sorry mate.


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[Hunter69]

Originally Posted by wilsonw2

Hmmmm. So ur saying idling will burn ur valves? I'm not challenging ur intelligence but I don't believe that. Sorry mate.


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if u remove the original exhaust and add a intake you will have no back pressure , therefore your valve seats will slam harder , at the end u will burn them. Ask a diesel engineer and see for yourself

[09Duramax]

Originally Posted by csdwarf11

haha! run it still it scatters? run it hard, make it happen! they will warranty it right?

yea, I don't plan to run it too hard cause it got brand new toyo m/t's on it that arent cheap!

[brstanle]

Originally Posted by Hunter69

if u remove the original exhaust and add a intake you will have no back pressure , therefore your valve seats will slam harder , at the end u will burn them. Ask a diesel engineer and see for yourself

What valves are you burning? Because adding an intake INCREASES back pressure to the intake valves. Also, the rocker arms let the valves close slower at lower RPMs, so they really shouldn't be slamming all that hard.