"Screech" Sound Upon Engine Shutdown

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I've had my truck for a week now, and since this is the first non-Chevrolet (and diesel) vehicle I've ever owned, I am getting used to the nuances of the diesel engine.

Question: When I shut the engine off, I hear a fairly loud and sharp "screech" noise that lasts just a split second. Has anybody else heard this? Is this normal?

Thanks in advance.

EJ

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'99 3500 QC,24V,SLT,white,4x2,AT,4. 10 posi,Mag-Hytec rear cover and trans. pan, Rancho step rails, Mopar bedliner

 

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Don't worry about that sound that you're hearing, it's quite normal according to Cummins. The big engine has so much compression that the engine stops quicker than the fan and fan belt!!! My good friend Don, a new Dodge TCD owner is on line and just registered today!!! Welcome SARGE----Sam

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1999 Dodge Laramie SLT QC TD 2WD auto trans long bed, LSD, HD towing and camper pkg, all options except leather

 

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When mine shuts off it's like the motor stops reciprocating, but all the stored up energy in the flywheel is then looking for somewhere to go. The whole truck shakes for what seems like a couple seconds with me in it!

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98. 5,24v,3/4 ton,2wd,lsd,5sp
blue box hp enhancement

 

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Yes, they all do that (the shudder of death when you turn it off). Helpful hint-don't have coffe balanced on the steering wheel when you put that cummins to sleep-it'll fight back!

-dm

 

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My 98. 5 24V has done the same thing since the day I bought it. . (or should I say, since the wife and the local BANK bought it for me. . #ad


I thought the sound was related to shutting the engine off while the A/C was still on. .
(NOPE. . )

This sound is DEFINATELY the fan wanting to continue to turn due to the built up inertia it has.
When you shut down the Cummins... (due to the high compression ratio). . it will stop. . LIKE NOW!!!!
The fan will want to continue to turn. . the "Skreech" is the rubber of the belt stopping the fan pulley.

I wonder. . How will this wear pattern affect the life longevity of the belt itself?
One would think this would speed up the belt wear and may even "Peel" the rubber off a belt prematurely.

Members???? Any thoughts??

As always . . Opposing Viewpoints are welcome.

Larry Quinn

 

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Larry, I'm not sure if it speeds up belt wear or not but my 94' chirped like a bunch of birds for 4 and a half years, even went and bought a new belt but never had to put it on. Now I still carry one for the new truck but I don't think I will need it any time soon. regards, Pete

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99'3500,quad cab,4X4,a/t
3:54

 

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My '96 always squeaked from day one, my'97 has never squeaked once. I saw posts on the old board that said the use of a Goodyear Gatorback belt would eliminate the squeak.
For the benefit of new truck owners, you might want to check out the "frequently asked questions" (faq's) page on TDR writer John Holmes' website. Here's the address:
http://www.ramblin.com/TDR_Menu.htm

You'll find answers to a lot of the questions that every new truck owner has.
Hope this helps, Andy

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'97 CC 4X4 5-Speed, on cover & page 91 of TDR issue 24.
Be sure to visit Northwest Custom


[This message has been edited by Andy Perreault (edited 09-05-1999). ]

[This message has been edited by Andy Perreault (edited 09-05-1999). ]

 

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That's pretty good Andy. I should have known JH had a site of his own. That would explain why we don't see him here. I just expected he was out wrestlin' doggies, and didn't have the time. Gracias.

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98. 5,24v,3/4 ton,2wd,lsd,5sp
blue box hp enhancement

 

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Speaking of John Holmes, MARK YOUR CALENDARS: Next year's May Madness in Minden, Nevada will be May 22-25. Yes, it will start on a Monday. My guess is that he scheduled it like this to give people time to drive there over the weekend from points east. There should be info about it in the next TDR. Peter Campbell, can you make it out west from New York? How 'bout Scott1, eh? Come on down from Canada, eh!
Andy

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'97 CC 4X4 5-Speed, on cover & page 91 of TDR issue 24.
Be sure to visit Northwest Custom

 

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Dont be misinformed..... there should be no high pitch squeek when you shut off the engine regardless of whether it is new or old. It is the belt, but if it squeels when you turn it off you need to replace the belt with a high quality belt when you shut the engine off no matter what everything else should stop.

 

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IMHO, due to the excessive compression ratio of a diesel engine, the rotating mass will stop quite quickly and "violently". This quick stop will often cause belt driven devices that have a lot of inertia to continue to spin due to the fact that the belt doesn't have enough friction to bring them to a "screeching" (no pun intended) halt.

-dm

[This message has been edited by dmurdock (edited 09-05-1999). ]

 

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As for the belt "screech", after working on this product for the last 12 year in pick-up, r/v's, gen sets, drill rigs, and a host of odd equipment. The belt noise happens on 8 of 10 engines. If you look at your belt tentioner it is spring loaded. with the driving of the fan drive/alt, water pump with the pull off the belt off the bottom of the crank ; it causes the belt to lift harder against the tentioner. Once you turn the engine off; due to built up compression; it tries to reverse direction for a fraction of a second. this causes the belt to throw the driving force from on direction to another. this causes a slight anount of slack on the belt that the idler can't regulate because the waterpump, a/c,fan, and alt pulley still have not changed dirrections. I have not seen and premature failures because of this. And yes, some belts work better than others as per the noise; also there are different idlers (frontside, backside, groved and smooth pulley)

 

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As for the belt "screech", after working on this product for the last 12 year in pick-up, r/v's, gen sets, drill rigs, and a host of odd equipment. The belt noise happens on 8 of 10 engines. If you look at your belt tentioner it is spring loaded. with the driving of the fan drive/alt, water pump with the pull off the belt off the bottom of the crank ; it causes the belt to lift harder against the tentioner. Once you turn the engine off; due to built up compression; it tries to reverse direction for a fraction of a second. this causes the belt to throw the driving force from one direction to another. this causes a slight anount of slack on the belt that the idler can't regulate because the waterpump, a/c,fan, and alt pulley still have not changed dirrections. I have not seen and premature failures because of this. And yes, some belts work better than others as per the noise; also there are different idlers (frontside, backside, groved and smooth pulley)

 

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I have noticed once I put the horton fan clutch on, and of course I shut off the A/C to let the turbo cool down fully that the screech has stopped. A little high dollar to stop an inconsequential screech.

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P. Campbell 1998. 5 ISB 2500 auto green/driftwood, driftwood rickson's 19. 5's, stainless Pro-Zap front bumper, Mag-tech diff cover, Northwest customs mudflaps all around, Genos/westack boost/EGT,trans/diff temp, etc--

 

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Yes, but there are other reasons to have the electrical Horton fan.
1. when not engaged it robs less horsepower from the engine. The viscus fan is at %15 lock-up.
2. when engaged it is at %100 lock-up, not 80-85%.
3. you can set the fan to run on manual, automatic,water temp, a/c pressure, and charge air temp (also know at intake manifold temp)

 

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Those are the reasons I added it- saying it was to stop the screech was tounge in cheek. Also as well as more power over time available(efficiency/fuel economy) and better summer cooling on demand. It also gives the faster warmup. Real nice idea. I did not know that it would run on charge air temp. I just installed it and it automatically controls on high refrigerant pressure and water jacket temperature, as well as the manual switch. But no intake manifold temerature sensor. Mabe it is not the most limiting???

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P. Campbell 1998. 5 ISB 2500 auto green/driftwood, driftwood rickson's 19. 5's, stainless Pro-Zap front bumper, Mag-tech diff cover, Northwest customs mudflaps all around, Genos/westack boost/EGT,trans/diff temp, etc--



[This message has been edited by Peter Campbell (edited 09-06-1999). ]

 

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I was addressing the different ways if could be set-up. In other applications the ECM controls the fan, one of the items it looks for is intake air temp. For your application you could add another sensor and some wire. But, what you have is a great system

 

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That noise scared me the first time I heard it, too! I believe that you will find that it's the fan belt.
Dean

 

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OK, guts, I was the one who posted the comment on the old forum about the Goodyear "Gatorback" belts stopping the squeek. Cmechanic is correct in his assesment of what causes the noise, and it has been my experience with two separate trucks that the Gatorback belt was a permanent cure for the noise. The design of this belt is that it has offset "cogs" in the grooved side. These evidently increase grip in both directions, so upon belt reversal, no noise. I figured that the accessories also have a better chance of rotation at crankshaft speeds. I had to order mine though a Good year dealer. Some parts stores stock them. IMHO, worth the $$$.

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John H. -'99 White Sport 4x4 QC SB, 5spd. w/GV od, 4. 10, American Racing SilverAtlas mags & stainless hubs w/Dunlop 285/75R16's, CMI 3000 cap, Mopar fender flares, Linex, Luverne stainless boards, Q-logic bass, Painless Wiring, BriteBox and soon Ted J. 's 4" exhaust w/US Gear 4" Decellerator.

 

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I meant, OK guys... . can't type after ten... . see ya.

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John H. -'99 White Sport 4x4 QC SB, 5spd. w/GV od, 4. 10, American Racing SilverAtlas mags & stainless hubs w/Dunlop 285/75R16's, CMI 3000 cap, Mopar fender flares, Linex, Luverne stainless boards, Q-logic bass, Painless Wiring, BriteBox and soon Ted J. 's 4" exhaust w/US Gear 4" Decellerator.