erratic knock sound with video

[turboGMC]

It sounds like a knock that fades in and out kinda. It goes away I think if I touch the gas or whatnot. Im hoping its my pmd. When I was under'er, it sounded like it coming from the dust cover but it was hard to tell with all the noise. Im gonna try to scope it tonight. Any thoughts?


VIDEO- 11.74 meg (http://www.angelfire.com/alt/bigshabstyle/startup.MPG)

[Polar Diesel]

maybe loose torque converter bolts??

[David Brady]

TurboGMC,
That rattle sure sounds like mine but its been the same since I bought it. Maybe I missed it but I didn't hear anything out of the ordinary.

[Turbine Doc]

Sounds pretty much like mine, is this with a cold or hot engine mine has similar maybe even more pronounced with the hi-pops when cold until it comes up to temp, is this a new noise to you, what I mean is it something you did not have before or have you had it since your 6.5 odesy began?

[JTodd]

It sounds like mine! Does that mean something is wrong with it too? Seriously, mine is very 'rattley' when cold, maybe more than your video. Once warmed up, it is still loud, just not as much rattle. You may have a noise caused by something loose that the video is not picking up sufficently because you both hear it and feel it in person.

[john8662]

I noticed that when I record one of these diesels that the knocking sound seems more pronounced due the echo the sound makes in the mic. Is this just when cold? I know that once underneath my 6.2 that it makes a similar sound, but you can't hear it normally from above. I also note that when my 6.5 is cold it had the sound a little bit till I reved it up and drove it a little bit to get it warmed up, then it goes away. It only happens at the point right before it is cold enough for the computer to do the fast idle. If it does it when dead cold (during fast idle) or when fully warm, then I'd look into something.

But, then again, the sound your engine is making, sounds louder than it should be, IMHO.

In Looking for knocks, you might also check your dampner pulley on the crank harmonic balancer. They have been known to deteriorate, the rubber breaks down to the point that is is loose, look carefully at that for cracked or missing rubber pieces.

[ 05-05-2004, 03:15 PM: Message edited by: john8662 ]

[whatnot]

Does it sound as bad outside the cab? If not, I would carefully lookover all the injector lines and make sure noting is touching them. Mine was making a similar noise and it was the heater pipe touching an injector line.

[turboGMC]

This "knock" or "rattle" is only pronounced when it is hot, usually right when I start it after sittin a few min. The video doesnt do the rattle justice, but you can hear it. Youll notice right when I startup it does a quick 5 knocks then 2 then just blends in. Thats the one im talkin about. Its usually doesnt sound like that.

Polar diesel~ I was thinkin the same thing and I had my ear dam touchin the dust cover but I jus couldnt tell if it was comin from my exhaust or what.

tbogemirep~ Well ive only had my six-five for 6 months so im not sure if it was there before. At cold startup its just plain ol' loud dieseling, if that makes cents. I dont notice the defined, fading knock at that point.

john8662~ ill check the pulley,thanks.

whatnot~ Its about the same when I walk round it. maybe a little lighter. ill look at my Inj lines thanks..

[kowsoc]

If you are talking about the higher pitched "ting,ting" sound, that has to be one or more leaky injectors. My Dad's 96 has sounded like this for 100,000 kms and not gotten worse so I don't think there is any harm being done....just an annoying noise at idle. His does not make the sound on a cold start or when ambient temperatures are below freezing, just at hot idle. When were the injectors done if ever? I think new ones will make it run like new! ;)

[Polar Diesel]

i've never heard a 6.2/6.5 that sounded alike. all power strokes and cummins all sound alike, but not our diesels! Nothing like being an individual.

[ssybert]

The beautiful pur of a PowerStroke. What was I thinking :-(