Tow Vehicle engine noise - Normal???

[Cardinal camper]

I just purchased a 2001 Chevy 3500 with 6.6 Duramax. This is my first Chevy diesel and it just seems to be loud inside truck while towing. The sounds is almost like a gas engine low on oil. Kind of a knocking sound. Is this normal sound for this engine? Tks!!!!

[avolnek]

Typically they will make more noise, a duramax shouldn't be as noisy as a cummins by any means.

There is a line though where too much noise isn't right... Any way you could post a video of what you are hearing and or concerned about? Hard to verify without actually hearing it.

Something to remember is a diesel creates a LOT More pressure inside the combustion chamber so things WILL rattle. Speaking of the cummins at least, my fuel injectors are running in the neighborhood of 7,000 psi at an idle and up to around 20,000 psi at full throttle! things are going to make noise!

[Brother Les]

You would get the best answer on a Chevy truck forum from owners that have had your type of truck for many years. I have owned my Diesel for 10 years and I would swear that it 'sounds' different every time I get in it. Sometimes smooth as silk and sometimes rattles and rocks. Pulling a load will change your RPMs and shift points a little. Have you had a chance to change your oil and fuel filter out for new? The Diesel fuel is a winter blend and will change things a little. Does your truck have a Chip or Tuner? There are different tow modes that will in a sense change 'the sound' of your diesel. You may have to pull your valve covers and re torque your rocker arms and injectors. There are many other little tweeks that may need to happen that the former owner has not kept up on.Don't know a whole lot about your Duramax, but I know that it is a very fine engine and truck. Learn as much as you can from a Chevy forum and you will be having a perma grin all of the time....

[hrlyguy2]

Since you have a lb7 motor.They are common for bad injectors..I would have your balance rates checked.I have alot of friends with lb7s alot of them use a quart of 2stroke oil tw3.which is a ashless oil to a tank of fuel to help with lubrication.
Can get a good additive too at Napa to clean up injectors

[Chewie]

Is it the pilot injection shutting off at a certain rpm?

[whj77372]

I would expect a 2001 Chev diesel to be nosy.

[jevanb]

since you have a 5 speed and sitting @2k or better towing heavy 65MPH it is going to be louder then a gas motor at that RPM, if you remove your foot from the pedal does the noise go away some??? as these engines evolved they also got quieter, I would agree on the valve train need adjusted, the inj are 200k warranty and it sucks to replace them, most LB7`s have had them done before that also, check the bal rates with a scanner should be <>4.0 and do a injector return test, go to Chevy and GMC Duramax Forum and do a search

[ckehl2]

I owned an LB7 for several years, it was my first diesel. As other have stated the injectors are prone to problems. An injector in my truck failed and caused over fueling which in turn cracked a piston. Please be proactive and have those balance rates checked. A new diesel motor is not a cheap undertaking.

[dsrace]

Originally Posted by hrlyguy2

Since you have a lb7 motor.They are common for bad injectors..I would have your balance rates checked.I have alot of friends with lb7s alot of them use a quart of 2stroke oil tw3.which is a ashless oil to a tank of fuel to help with lubrication.
Can get a good additive too at Napa to clean up injectors

good info and I have 4 friends with duramax's and they all started using 2 stroke oil and it did quiet the inj's down to the ear. I put rev x in my ford

[dsrace]

Originally Posted by ckehl2

I owned an LB7 for several years, it was my first diesel. As other have stated the injectors are prone to problems. An injector in my truck failed and caused over fueling which in turn cracked a piston. Please be proactive and have those balance rates checked. A new diesel motor is not a cheap undertaking.

that's no joke they are very expensive especially if you can't change it yourself

[dsrace]

Originally Posted by Brother Les

You would get the best answer on a Chevy truck forum from owners that have had your type of truck for many years. I have owned my Diesel for 10 years and I would swear that it 'sounds' different every time I get in it. Sometimes smooth as silk and sometimes rattles and rocks. Pulling a load will change your RPMs and shift points a little. Have you had a chance to change your oil and fuel filter out for new? The Diesel fuel is a winter blend and will change things a little. Does your truck have a Chip or Tuner? There are different tow modes that will in a sense change 'the sound' of your diesel. You may have to pull your valve covers and re torque your rocker arms and injectors. There are many other little tweeks that may need to happen that the former owner has not kept up on.Don't know a whole lot about your Duramax, but I know that it is a very fine engine and truck. Learn as much as you can from a Chevy forum and you will be having a perma grin all of the time....

I used to experience this with my 99 psd until I installed a fuel recirculation kit which also raised the fuel pressure to 65 psi.....90% gone now.f I installed that when I pulled the turbo to install the wicked wheel II and what a diff that made in performance but quieted the turbo down too.