There have been a few threads about the LB7's ear-splitting whine. I don't recall that anyone has posted a solid answer about where it comes from or what to do about it. This is not the turbocharger whistle that some list members are seeking. This is a high-pitched, electronic-sounding whine that is emitted when under light throttle and between about 1500 and 2000 RPM. Another trait is that the boost pressure is generally between 2 and 3 psi when it is being produced. When I'm running solo it comes and goes with various driving conditions, but when I'm towing the trailer, flat, level, steady driving creates the right conditions, and this thing whines away for extended periods. After a few minutes my head feels like it's going to split open. It's bad enough that if I can't do something about it the truck has got to go. The dealer says it is normal turbo whine. I don't know if all LB7s have this problem, but there have ben enough threads about it that I know I'm not alone.

After 2 years of on-and-off fiddling around I'm pretty well convinced that the whine originates in the turbocharger and is being amplified by the heat shield. (When running with the heat shield removed, or with its ends anchored, the whine is not as loud). I've also found that I can come close to eliminating it by propping the wastegate open a little. With the wastegate propped open by about 1/8 inch of pushrod movement, the amount of time that the whine is emitted is reduced by about 90%, and its intensity is lowered to below what splits my head open.

Before messing with the wastegate my maximum boost was 22 psi, and I did 0-60 runs in 10 seconds. With it propped open the maximum boost is 18 psi, but the 0-60 runs are perplexingly unchanged.

For thoise that know more about turbos that I do, I'd like to ask if I'm rsking any long tem harm by having the wastegate permanently opened a little bit.

I honestly have no idea what you are talking about.

Do you hear dog wistles or do you have ears like a bat? My truck dont do it, dosnt sound normal.

I'm sure Juice could enlighten you about that wastegate....:rolleyes: ):h

About the only time I hear a constant whine is when I'm towing our travel trailer. Its a 30' trailer weighing about 7500 lbs. Wayne, if that is what you are referring to, I would double check the insulation on your firewall. Also check to make sure you have no open holes in the firewall where one of the rubber grommets did not seal properly. The whine may be there most of the time while towing, but it should not be loud enough to be bothersom.

Yeah, I have no idea what you're talking about either.

But being an audio idiot, here's some dumb questions:

1) what's the pitch? Is it a drone like when you blow across a coke bottle making it resonate at lower midrange (200Hz). Or is it higher, like a cell phone beep (maybe 1000Hz). Or higher yet would be a tapping of a champagne flute or a cymbal. Normal turbo noise is maybe 5000Hz and up. Mine was singing away tonight under the same conditions you describe. When I have my foot totally in it, it's just a "whoosh" sound but when you're light on it, it rings like a bell.

2) have others heard it? What do they think?

3) is it louder with the windows down (and passing walls / bridge abutments / etc?)

I'm surprised it drives you nuts, because it can't be much louder than 75 dB. It's probably a frequency sensitivity thing.

DO NOT buy an AFe stage II intake kit. Mucho singing. http://www.dieselplace.com/forum/images/smilies/hihi.gif

There is one tool at work that will drive me from the room - an ultrasonic welder. No one else really hears it very much, but it's like needles being driven into my brain. So being the nerd I am, I got this little frquency analyzer for my laptop, and found that it was pretty high in level (80ish dB) and the frequency content was almost all 18 kHz.....which is way up there for human beans.

Took five years for me to find it. Second times a charm... been 15 years.

I don't know how or what could be such a nusiance to you either. I DO know that I pulled into the garage and shut down one time and was futzing around with the mail or something and heard a soft little high pitched whine from the center of the dash. I thought "what the HECK is that? - especially with everything shut down - and then it STOPPED!" Come to find out, it's a thermostatic cooling fan on the OEM stereo system. This couldn't possibly be the source, could it?

It doesn't sound like this is the problem, but I'll throw it out here anyway. You wouldn't happen to have an Isspro EGT gage with the little amplifier box would you?

Steve

I think i have heard the noise you are talking about but only 2 times when i was letting the truck warm up. I could actually hear it from inside the building. By the time i went outside to get in the truck to go home i couldnt hear it. To the guys that havent heard it, it is a very high pitch noise and to go with NWPADMAX its probably around 3000hz. My truck is an 02.

Could one of the air in or air out pipes be leaking?I know on a big Cat if one of those come off it will take your ear drums out.????

Thanks for all of the replies. I'll try to answer some of the questions raised. Here is a good description of the whine, written by somebody else in late 2003:

From day one I noticed a high-pitched whine that seemed associated with increased engine speed. It appears to be electronic in nature and seems to track with the acceperator pedal movement. I can be at speed, push down on the go pedal for more speed and I hear the electronic whine. It sounds to be coming from behind the dash and to the left of the speedo cluster.

This poster did not think the source was the turbocharger, but I am now convinced that it is in fact from the turbo. Other posts have described it as being similar to audio system feedback.

I estimate the frequency to be at least 10,000 hz., probably higher. It's definitely a frequency issue as opposed to a sound level issue. There's no Isspro gauge installed, and it's not the radio fan. I'm pretty sure that all of the firewall grommets are in place because I had a heck of a time finding a place to punch through for the tube running to the boost gauge I recently added. And, no, I don't hear bats.

It's probably just the turbo whine if it's that high in pitch.

Have you driven anyone else's LB7? If we all have the same thing, then maybe this ain't the truck for you. Find a member close to you and PM them for a test drive.

Mebbe you could take an '05 LLY for a test drive and see if it's better.... if it is, trade the whiner in http://www.dieselplace.com/forum/images/smilies/hihi.gif

I noticed that same sound the first day I got my truck. Sounded kinda like an alternator whine, only a lot higher pitched and it does seem to track with the engine/throttle... Also, it does seem to be coming from the left side of the vehicle..

That said... I can't remember the last time I actually heard it.. I musta got used to it and now just tune it out...

L8r...

[QUOTE=nwpadmax]It's probably just the turbo whine if it's that high in pitch.

Have you driven anyone else's LB7? If we all have the same thing, then maybe this ain't the truck for you. Find a member close to you and PM them for a test drive.QUOTE]

If you go near Cleveland, you could drive mine. It has the whine too, it's the turbo, probably closer to 20Hz. :cool2: sound!!!! ):h Best part of driving a turbocharged diesel.

You ever make it out towards Wilsonville?

wayne, you are not crazy. my 2004 lb7 has the same problme, it comes and goes and it is alwayes at low to medium speeds. my gut feeling it is something in the sound system.

You could possibly have ear Tinnitus, but I am not a Doctor.

Last week we went for a drive and on the way back I heard that noise, I slowed but the noise stayed the same. I thought well when I get home and shut the truck off I'll know? Got home shut the truck off and the noise was still there.
Went to my ENT and he examined my hearing and ear and stated I had Ear Tinnitus case closed, truck was fine.
:):)

Try leaving the wife home. All my in cab problems cleared up.

I honestly have no idea what you are talking about.
I think Grandpa has feedback within his hearing aids..:p:

:funnypost Tony