Noisy LLY Duramax

[wzschirnt]

Hi,

This may have beat to death, but I'm kind of new to diesels, so here goes:

I've had my 2006 2500 Duramax for about a year and it tows the race car trailer wonderful. But it is a noisy son-of-a-gun! Sounds like there is a lifter about to bust out of there. No miss, etc, just noise.

Is this 'normal injector noise'? I've taken it to an 'diesel expert' shop and they say "Normal". It is just that I've heard several other DMax's (similiar years) and only mine will make you turn around when I drive by.

If you say no problem, I'll just turn up the radio.

Thanks
walt z.

 

[S Phinney]

Most likely not normal. Need to check injectors and turn them off one at a time to see which one I S causing the noise.

 

[ALLY Fox]

LLYs do tend to be noisier than LBZs, not sure why but it's a whole different system. Did your "diesel expert" do an injector balance rate check? That would be the best first check to see if something is going on. I had one injector that would get noisy every so often, sounded like the pilot injection would turn off at low RPM. Balance rate check showed #2 at over +4, replaced it and no more noise! Also, do a search for "icepick fix", yours might need some intervention.

 

[superswamper003]

The 06 llys are lbz. Just detuned!

 

[minerigger]

This ^^^ I have one...Curious if I have gay pistons and ok rods or if I have bamf pistons and gay rods

 

[minerigger]

Always wondered that on these lly Vin coded lbz's

 

[coldLBZ]

2006 LLY's have the same rods/pistons as LBZ's. The only difference is the tuning.

 

[minerigger]

I figured. Thanks for confirming

 

[wzschirnt]

LLYs do tend to be noisier than LBZs, not sure why but it's a whole different system. Did your "diesel expert" do an injector balance rate check? That would be the best first check to see if something is going on. I had one injector that would get noisy every so often, sounded like the pilot injection would turn off at low RPM. Balance rate check showed #2 at over +4, replaced it and no more noise! Also, do a search for "icepick fix", yours might need some intervention.

Balance check was done and all were "real close" (mechanics words). Between 1.5 and 2 if I remember the numbers right.

"Icepick fix" has to do with loose connections at the injector. right? Is a loose connection something that would cause a LOUD 'ticking' while running down the road. Again, I'm 'new' and just trying to get my head around this diesel deal.

Thanks,
walt z.

 

[Awenta]

Can you tell where the sounds is coming from? Bad vacuum pump?

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[02greysixer]

Can you tell where the sounds is coming from? Bad vacuum pump?

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To my knowledge the only Duramax that has a vacuum pump is the Cali emission lb7.

O.p. If you don't have any kind of misfire, vibration, your fuel rail pressure is what it's supposed to be and there isn't excessive crankcase pressure the only other thing you can do besides having the injectors tested by a Bosch test stand is checking valve adjustment.

 

[NC-smokinlmm]

Run a double dose of diesel power service in the grey bottle and see if it gets any quieter...

 

[pizza pig]

All my balance rates are good, yet one knocks at certain pulse width and rpm and another has a constant tingy tick while on the throttle at certain pedal positions. It annoys the hell out of me. Its really hard to say without getting the injectors tested, or if thats even the issue. :woott:

 

[02greysixer]

Mine has a random rattle/knock as well. Since I never have time to work on my own truck, my "fix" (temporary bandaid for going on a year now) is to occasionally dump a quart or two of 2 stroke or motor oil in the fuel at fill up. My noise went away so I know it's injector related. Just a matter of waiting for it/them to get worse to pinpoint. It's not ideal but it is still keeping mine quiet

 

[Hot COCOAL]

These ideas are a long shot, but...

An injector hold down thats backed off and allowing the cylinder pressure to escape the injector seal sounds allot like what you're describing...

Check for any residue near all the injectors, you can also pull the fender liners and stick your head in the wheel well when the engine is running and see if you can smell fuel/exhaust...

Also check the connection at the exhaust manifold to turbo up pipe and up pipe to turbo connection... A tiny leak at either one of those points can sound pretty raspy like a ticking sound

The only thing i can think of that would immediately eliminate either/both of those two ideas is if the noise doesn't change with and match RPM...but im guessing the noise does

Other than those ideas, and the injector tests and the option to try out some diesel additive or 2 stroke oil in the fuel, the next thing to do would be to pop the valve cover(s) off and take a peek at the valvetrain and measure valve lash...

 

[wzschirnt]

I run Diesel Kleen each fill-up.
So, the consensus is that this is not a 'normal' sound??

Guess I'll think about valve adjustment.

Thanks.
walt z.

 

[wzschirnt]

Ok, so a new 'guess' by another 'expert' is a leaking injector.
Going to have them do a diagnosis this week.

So, questions:
- Is there a way to narrow down which injector it is? He (the shop expert) made it seem that replacing all is the solution. Pretty expensive deal just to make it quiet!!
- Or, are there other problems that can be caused by a leaky injector? There's no smokey exhaust, no blow-by; truck runs great, good mileage, no miss, just "clack, clack, clack".

I just want to know if it is just noisy or if it will blow-up if I don't get it fixed?

Truck currently has about 185k and no telling how long it has made the noise.

Thanks,

walt

 

[c20elephant]

Another shot in the dark, purchase a mechanics stethoscope and listen down by water pump, from what I have read they make some unique noises when they're on the way out.

 

[Awenta]

With a tech2 you can turn off injectors one at a time.

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[Veikra]

Mine is noisy until exactly 72 Celcius engine temps. It will not get quieter as it warms up, it will straight up go from noisy to quiet the next second. It's not lifters, just been done to 10 thousands all around.

If the engine gets hotter, it goes silent and if it cools down while running (winter) it will start getting noisy again. It's still weird that it's so sharp.

I'll shotgun all the injectors soon, pretty sure 225 000 miles is too much asking of them. In the meantime I baby it til it's warm and silent