Engine/Transmission (1998.5 - 2002) Loud popping noise in the air cleaner area, Is this the infamous turbo 'bark'?

[RThompson]

Heard what I thought was wastegate popping off but need to confirm the sound and conditions.

Conditions,, pulling 7000 lb load up 6% grade about 55mph in 5th gear, motor temp normal, outside temp about 50 degrees, less than 10,000 on the odometer. The throttle is nearly all the way down and there is 3 loud pops from behind the heater assembly. Happened again, same circumstances about 500 miles later. Didn't have any other problems other than scaring hell out of my bride as it is coming right below her feet. I have full set of gauges now to monitor this if it happens again. Turbo bark??

 

[TERMINATOR]

RThompson turbo bark happens when you let off pedal fast. I have never heard of turbo bark on excelleration .

 

[klenger]

Did it sound like your right front tire was flat? Several have reported this sound on the 6 speed climbing in 5th gear, but no one has an explanation yet.

 

[Deezul1]

The turbo bark happens when under a lot of boost and a abrupt backing off on the trottle, if you ease out even quickly it wont do it.

 

[RThompson]

Klenger:

Steady pull for several miles out of the Columbia River gorge. I had backed out off of the throttle just a bit prior to noise to keep egt's down and was holding steady throttle at about 2500 RPM or slightly less when it cut loose with 2 or 3 very loud pops. It was very close to the heater core area and sounded like handgun went off under the hood.

 

[yogibear]

RThompson, what were your egt's when this happened. Do you have any mod's that are not in your sig. ? What air cleaner are you using. I'm asking because this happened to me a few months ago, but I could never figure out what it was, and it did not do any damage. ?/?. Scared the stuffing out of me, thought I'd blown up the CTD!!

Larry

 

[RThompson]

Yogibear:



Everything in the motor area is stock, including air cleaner and exhaust system. Fully expected to find some kind of damage when I opened the hood, but nothing. Happened again pulling over Techappi Pass out of Bakersfield, same gear, rpm and weather conditions. The motor still runs very good and it feels like breakin period is getting over, oil is clean amd oil pressure stayed the same. Gauges are now installed. (this got me off of the stump in regards to gauge selection) Leaving on long tour of the USA and would like to keep this going to maybe find some explanation. Selling dealers service dept. never heard of problem before, their diesel tech is on vacation so have to wait another week to talk to him. Really reluctant to stop into dealership on our trip, should there be more problems, to have stranger look at it. Thanks guys for all the input!



r

 

[RustyJC]

I've seen a number of reports of strange intake (apparently) noise when towing heavy loads uphill at higher RPM. Ours did it in stock configuration pulling our 5ver up steep grades.



Some people felt it was related to the duct between the air cleaner box and fender well. In our case at least, that doesn't seem to be so - ours still makes some funny "whoomps" at 2500 RPM or so under heavy uphill towing loads with the BHAF. If I were a betting man, I'd bet that it's due to the curved air inlet hose to the turbocharger creating flow stratification and turbulence - most engine manufacturers want 5 pipe diameters of straight pipe (i. e. , 15" of straight pipe for a 3" pipe diameter) going into a turbocharger to ensure stable, non-laminar and non-turbulent flow.



I've never heard of any problems being attributed to this phenomenon. Assuming you're hearing the same noise I am, if I were you, I'd hitch up, head out, enjoy my vacation and not worry about it.



Rusty

 

[yogibear]

This happened to mine before I got the B 1 Turbo, I was running awful high egt's, and the BHAF air filter. We thought it may be from the hot air being drawn in from under the hood. When this happened I was running 1250-1300* pulling a long grade, so temps. were running pretty high under the hood. Has not happened since. I did what RustyJC said, and keep egt's at 1250*, or below.

Larry

 

[Boldt's Wagon]

All at high EGTs? Might this be the exhaust manifold expanding more than the head and finally relieving the pressure? Maybe having the loose manifold bolts on #6 was good for eliminating this noise?

 

[ghalim]

I'm relatively new to diesels having only had mine about 2 months but I'm very familiar with centrifical air compressors which is really what a turbo wheel is. In a centrifical compressor a "surge" is a rapid reversal of air flowing backwards past the wheel and out the intake filter assembly. This can be quite loud and will make you jump out of your socks. When air flowing off the wheel suddenly has no where to go such as rapidly letting off the throttle or pressure builds beyond the wheels ability to sustain it the "surge" happens. Typically on centrifical air compressor this does not hurt them as long as it stops after a couple of surges. Each time the air is compressed it naturally heats up. Rapid surging takes hot air and reheats it over and over. This will litterally melt down a compressor if not stopped.

Sounds like everyone is only experiencing this sound once or twice and then it's over thus no apparent damage. However having never hear a diesel do this I'm only guessing.

 

[RustyJC]

ghalim,



I know that you can't find them with the search function down, but there have been a number of discussions on this forum regarding centrifugal compressor surge. The phenomenon we're discussing here does not sound like a full-blown surge - that normally happens when one "chops" the throttle, instantaneously killing the drive energy to the turbine while boost is still present, thus producing sequential flow reversals during spooldown. The constant throttle, heavy load sound we're discussing is (at least in my experience) often more of a "thump" - in fact, some people have pulled over to check for a knot on the right front tire!



Rusty

 

[JJW_ND]

6sps only???

I going to guess those of you with this sound all drive 6sp?



My work truck (2001 6sp) does the same thing but only when it is good and warm (after pulling a good hill awhile) and in any of the top three gears. I chased and chased this sound last spring when pulling through the MTs of WY. I was convinced it was from either the exhaust of some part of the engine touching the body. I could make the noise come and go at pretty high rpms and again only after I had been pulling a grade for a while.



I waiting for one of you to identify exactly what is causing it. I don't think it has anything to do with the intake. Engine runs fine, coolant temps fine. Noise seems to come form transmission housing area or forward on the passenger side.



jjw

ND

 

[RThompson]

Thanks!!

Some good stuff in these replys. Will keep you posted if I can come up with any answers. Next time it happens I won't be so quick to get out of the throttle. Gauges maybe will give some more clues what it takes to set it off.

r

 

[Un-Hemi]

I experienced some pops that sounded like backfire when I was towing across the rocks last summer. The RPMs were up there in second gear when it happened. Subsequently, I found out that my lift pump was toast, and I attributed the backfiring to that. Haven't had the opportunity to try towing since. Hmmmmmmm...

 

[rob10858]

we'll finally we get to the strange sound that all of our 2001 and 2001. 5' have had from day one . we all call it the "ghost in the machine" because it is only in 5th, only on long hard pulls, and leaves as soon as it appears. our guess... cavitation of the filter inside the box, or cavitation of the whole box under certain torque ranges. why they only present themselves at fifth gear, i'll let you guys fight that out. i think everyone would agree that the biggest weak point on our trucks is the induction system, and what we hear is our baby's begging for more air. imho

 

[merryman]

Texan Bill Stockard reported this remedy(done for him by Carson Dodge at may madness, I believe in 2000 . I was doubtfull and put up with "the noise" on my ethdee till five months ago when I made the change. After making his change, we made a 4K mile trip to Az and through eastern Nevada and back grossing 19. 5K+or-, I did not experience the noise once!

Carsons explaination as I recall, was that it had to do with water flow in heater hoses and the heater core. The cure was to re-route the heater hose from a port near the rear of the head to one near the front.

Nope, doesn't make a lot of sense to me either, but since after doing so, many hard pulls with a big load did not produce the noise a single time.



Vaughn

 

[Larry Willard]

I too along with at least one other person had that repair done at Carson Dodge with good results, although it would occasionally still do it lightly on a really hard pull.



Larry

 

[RThompson]

Bringing this old thread back up to see if anyone has had any luck with the heater hose reversal as 'merryman' posted. That is a classic look "outside of the box" to affect a repair! Just don't see how coolant rerouting can silence something this loud.

But, can't hurt much to try the remedy.

 

[sag2]

Sounds like the water hammer problem. TSB 09-008-02 gives a new thermostat PN for this problem. If you have never heard this noise, you would never believe it is coming from the cooling system. You will only hear it pulling considerable weight on a very long pull in hot weather.