rattle

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There is a rattle up front just after cold startup in the morning. It sounds like the timing chain. I replaced the tensioner with no change. It's worse in colder weather and if I park in the driveway with nose down.

Changing from Rotella T 5W40 to Mobil-1 10W30 helped slightly.

Motor was rebuilt 15k miles ago. All timing components were replaced but the tensioner.

I was going to pull the valve cover and try to inspect the chain guide & slipper, but I figure it would rattle all the time if they were broken.

What could it be?
 
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It is probably the normal start up rattle that most people experience. Mine noise came from that area. Which oil filter are you using? Swithching to the smaller style filter helps a good bit. I changed to the smaller Napa Gold filter and mine completely went away.
 
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mooker82 said:
I believe on the FZJ there is not timing belt or chain(it is gear driven). .

close but other way arround, 91/92 FJ80 has the 3FE, direct gear driven cam pushrod motor. 93-97 FZJ80 has the 1FZ-FE witch has double over head cam and a timing chain. (see my avatar for pic of my 96)
 
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Yeah, I saw that. It's not a growl like a wheel bearing or PS pump. More of a tapping noise like the chain is touching the timing cover.

I noticed the chain in there when I rebuilt it ;).

thx, eric
 

IdahoDoug

 
 
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Cman,

I have a buddy with a fairly steep driveway so I park nose down there. When my truck idles warm in this position it makes a funny semi-rattle, semi-deep rattle sound. After a few suggestions years ago, I kinda subscribed to the theory that it's from the front rods slapping the oil since the block is so long. May or may not be relevent. I remember hearing this sound a decade ago while wheeling when the truck was new, so it has not changed.

Also, the PAIR valve can make some funny rattly sounds on my 93. Ever notice the engine will make a very brief rattly sound after you've shut it off and just as the engine completely stops moving? Again the 97 does not do that. The 97 doesn't have the PAIR on it since the emissions were updated. Wonder if that's it?

Finally, there's that interesting 'split' gear on the front of the exhaust cam. Wonder if that can generate such a sound?

Anyhow, if you do pull the valve cover, I discovered last week you can pull it with only the throttle body removed. Remove the top bolt on the heater hose that's right by the EGR valve and those pipes/hoses will flex enough to pull the valve cover up and forward. Just pull all the spark plug wires and toss them atop the intake manifold. Having the hood off and a buddy there helps measurably, but if you get in there and stand on the right motor mount you can do it alone under the hood if someone will stand there by the front bumper and take it from you.

DougM
 
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Doug, I've pulled the valve cove so many times I don't need to remove the TB. J/K :)

This is a unique sound in my engine's history. If it were a 22RE I would say it's the timing chain, so that's what I think it is. What's got me curious is that all those parts are new (tensioner, guide, slipper, and chain), and the sound happens when cold.
 

landtank

SILVER Star
 
 
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My noise at startup has long been solved with adjusting the valve shims. They were all loose and once tightened the noise has yet to appear.
 
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Don't forget.... a noisey tappet is a safe tappet! ones that are dead quiet are the most worrying, as a tight tappet can burn out the seating of the valve where as a noisey one is ok, no harm done
 
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I don't think it's the valves, but worth a check. I put them at mid spec after rebuild, and they were the same 5k miles or so later. The sound is more up front than at the top.
 

IdahoDoug

 
 
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Describe it a bit more fully. Also, does it happen on each startup, or only the first one of the day when the engine's stone cold? How long does it last, etc.
 
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I know I'm telling you to suck eggs, but o the description you have given, it deos sound like the usual start up rattle, funny thing is, when mine is parked at an angle sloping downwards, when warm, it has a funny light rattle, and sounds like the chain is lightly hitting the cover, wierd I know but it does sound like that.
 
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The startup rattle is a full extended blast that immediately stops. This starts after the rig is running first time in the morning since the weather has turned chilly. It's more like a light jazz beat against the timing cover that comes on after the fan clutch roar is reduced. It lasts for at least a minute, but I haven't waited around long enough to see how long it lasts.

It's an irregular tapping that gradually reduces. I'll see if I can capture it digitally.
 

IdahoDoug

 
 
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Boy, this will piss you off if you've done a lot of disassembly chasing it. I think it's your idler pulley next to the A/C compressor. Mine sounded exactly like that for a while before beginning to do it longer. It would only last a minute or so on cold starts only, right? Never heard it any other time but in my garage in the morning.

Anyhow, I confirmed it was the bearing going using - what else - the wooden dowel trick. I could clearly hear distressed loud whirrings in that component and only normal sounds on all other belt driven items. Try it. If you have the dowel in place on your ear and have your wife start the truck you'll practically jump back, but you can hear it any time of day as well.

DougM
 
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Doug, That was my first guess, since it sorta comes from that area, but that's a strange sound for a bearing to make. I thought about pulling the AC belt, but never got around to it. That's easier than pulling the valve cover at least :).
 

IdahoDoug

 
 
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Eric,

That's why I posted it. It did not sound like a typical bearing, AND it went away after startup. Hope that's it as Cdan got me a new pulley, lock nut and looooooooooong adjuster bolt for less than $20 if I recall correctly.

DougM
 
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