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denjolicoeur
Dodge Dakota
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8/31/2004
10:05:22
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 Subject: 4.7 rattle on startup
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Hi guys,
I'm new here, recently bought a 2000 Dakota Sport with a 4.7 / auto.
After a few weeks of driving it, I just noticed this morning a loud rattling from the engine bay upon cold startup. It only lasted about 5 to 7 seconds then subsided. I never noticed it before, the passenger side door was open this time, allowing me to hear better. The wife said she'd noticed it previously. The truck has 120,000 kms (75,000 miles)
Has anyone experienced this? Any ideas on what it may be?
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daffydak
GenIII
8/31/2004
11:04:36
|  RE: 4.7 rattle on startup
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Mine does that too! I have NO idea what it is, it is def. NOT a lifter. it sounds almost like the chevy Piston Slap (my dad has an 01 chevy 6.0L that has P.S)
His sounds MUCH louder then what my 4.7L does though). his sounds like a diesel at startup..... mine sounds kind of like if you beat/rub 2 screwdrivers together (or on the side of the block). its hard to describe the sound.
does your engine sometimes idle rough for a few seconds on cold startup too? mine also slightly hesitates with moderate to heavy accellerator input (in neutral or in gear)
My 00 has a hair over 50,000 miles on it, and is in good running condition otherwise (recent plug change, NEW k&n air filter, new Flowmaster exhaust.) I have even tried repeated fuel additives, to no avail.. hopefully someone knows whats going on! I still have 1 1/2 years of warranty left. so if it gets worse, it's going to the dealer.....
Dan
MOPAR=More Power!!
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denjolicoeur
Dodge Dakota
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8/31/2004
13:14:16
| RE: 4.7 rattle on startup
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you wrote: "mine sounds kind of like if you beat/rub 2 screwdrivers together (or on the side of the block). its hard to describe the sound."
Yes... sounds like the same symptoms. Anyone now what's causing it?
I haven't really noticed any rough idle. It does seem to rev-up to about 1200 or 1300 on occasion just for 1 second upon cold startup; I'd assume that this was normal, just the computer setting the idle/choke. What I'm really concerned about is the rattle. I currently have conventional oil in it (whatever the dealer put in), planning to go to Mobil 1 10w30.
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daffydak
GenIII
8/31/2004
13:28:53
|  RE: 4.7 rattle on startup
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Oh I forgot to mention the oil I use. I use Mobil 1 5W-30 and a napa gold filter (I did use AMSOIL but I don't really have the money for that now :)
My oil pressure is allways around the center at idle and about 3/4 of the gauge while driving.
I'm a little concerned, especially with winter approaching! but since it runs fine otherwise, I don't loose any sleep over it.
about the rough idle... it only lasts about 3-4 seconds, and it sometimes almost stalls (drops to about 350-400 RPMs). it sounds like a small block with a HUGE cam (and yes my IAC and Throttle Body are clean) if i give it a lil gas, the rough idle never happens. It almost acts like its loading up, because the computer will rev it up to about 1,200 for a second then its fine....
Hopefully someone can shed some light on this for us.....
Dan
MOPAR=More Power!!
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99bludak
Dodge Dakota
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8/31/2004
14:07:20
| RE: 4.7 rattle on startup
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Message:
I don't have the problem with the noise, but mine definetely does the rough idle bit. It does exactly what you describe. It almost sounds like it is going to die, and then other times it revs up to about 12-1500 and then levels out around 1000 until I put it in gear. Nothing wrong, I think it is just the engines characteristics of warming up. Mine runs fine.
99 CC SLT 4x4 58000 miles
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Izzy
Dodge Dakota
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9/01/2004
09:26:15
| RE: 4.7 rattle on startup
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Mine has it also, I was figuring on a belt tensioner pulley going bad. I am at 99k miles and its an original.
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Figols
Dodge Dakota
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9/01/2004
10:32:21
| RE: 4.7 rattle on startup
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The rattle at startup is most likly one or more of the the hydraulic valve adjusters. This seems to be common with the 4.7L. It is like a bad valve lifter in a push rod engine. The adjuster bleeds down when the engine is off(much like a bad lifter)and then takes a few seconds to pump back up as the oil pressure builds. Mine has been doing it for about 15K miles and it does seem to be getting worse. I'll probably replace mine soon.
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daffydak
GenIII
9/01/2004
13:57:08
|  RE: 4.7 rattle on startup
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Message:
Do you think the adjuster would cause a rough idle until it pumps up? Either way, its time for me to make a service appointment with my dealer! maybe theres a flash to help with my rough cold startup idle (and low idle with A/C off) i'm also going to check my exhaust manifold nuts, for tightness. my 3.9L had a BROKEN manifold bolt, but it caused a much quieter ticking sound
(the noise my 4.7L makes is pretty loud!) the noise seems to be coming from the left(passenger) rear side of the engine. I bieleve that would make it around cylinder 6 or 8.
I just wish i could get a good quality recording of the sound (and have somewhere to host it) because i can't really describe it. it sounds louder then a noisy lifter, its mopre of a blunt tapping sound as opposed to a sharp lifter sound. If it is an adjuster, how major of an engine problem is it? should I baby my engine until I get it to the dealer? is it OK to drive normally (for me that means occasional WOT :)
Now I'm glad I bought the extended warranty :-)
Thanks.
Dan
MOPAR=More Power!!
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TexasTodd
Dodge Dakota
JOIN HERE
9/01/2004
19:46:14
| RE: 4.7 rattle on startup
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Message:
Chill,
It's just the viscous fan clutch.
You don't need it, get rid of it.
Then if it still makes the rattle, it probably wasn't it!
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Dino
Dodge Dakota
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9/14/2004
15:33:20
|  RE: 4.7 rattle on startup
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Message:
I had some oil pressure problems an heard a slapping noise and it was along piece of raping paper that when was torn of in the factory it was left in the pan! Went In the sump only got stuck there when it was cold season.
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