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Discussion Starter #1
So the other day, i was just crusing along and all of a sudden noticed a squeak/knock nois coming from the motor.

Pulled over and thought it was the belt, sprayed some dressing on it and did nothing. Got it home and really started looking. It is coming from the very front cylinder on the drivers side. If you grab hold of the sparkplug connector, you can feel a small vibration everytime the cylinder fires. it is not noticible in other cylinders, just this one.

It wont make the noise (or sometimes hardly) at idle or no throttle cruise. However, when you are under load, it is very noticable. The sound is rev matched with the motor.

Could this possibly be a broken valve spring?

There is no oil coming from the exhaust and does not smoke or perform any different then before.

I would like to have a list of possibilites before i tear the valve cover and heads off.

Thanks guys!
 

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I hate you people.
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More like a spun bearing but the only experience have with that is on a 2000 Toyota Corolla but it also burned oil when that happened.:huh:
You will probably need to drain the oil from the crank case and cut the oil filter open to check for metallic debris. Or pull the dipstick and rotate it in the light to see if there is any metal flakes and debris in the oil on the stick.
 

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It could be a bad bearing like Primus said. That would be my guess based on your description.

How is your oil pressure?

If it is a bearing you won't see it by pulling the heads and valve cover off, you will have to get the oil pan off to look at it. Since you have a 4WD, I am pretty sure the only ways to do that are to either pull the motor or to remove the axle. I think you also might be able to raise the motor on a hoist enough to remove the oil pan, but not sure if you will be able to reach the bearing from there. Assuming it is the bearing.
 

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Discussion Starter #4
Oil pressure is fine, however, after 2 30 min trips at hwy speeds, when i turned off on the side road, the oil pressure blipped to zero, check guages light poped on, then jumps right back up to normal.

But that was 2-3 weeks prior to this problem.

I'll dick with the oil & pan after the truck comes back from the trans shop.

Any other options on this?
 

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that could have been a warning sign. ive seen many many 318 and 360's pick up screens plugged with metal and debris causing it to loose oil pressure and knock on occasion. sounds like you already caused damage. if number 1 cyl is squeaking it would make sense because its the FARTHEST away from the oil pump thats going to be the part of the engine that will be staved for oil first.
 

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Discussion Starter #6
that could have been a warning sign. ive seen many many 318 and 360's pick up screens plugged with metal and debris causing it to loose oil pressure and knock on occasion. sounds like you already caused damage. if number 1 cyl is squeaking it would make sense because its the FARTHEST away from the oil pump thats going to be the part of the engine that will be staved for oil first.
It's not knocking by any means, its hard to explain. At idle it is a squeak as if the belt was squeaking. Just sounds more like a knock at higher RPM's because the sound gets meshed togeather.

I've had a main bearing go out in the 3.9L and it was much different then this, i feel safe to say that this isnt the problem.

im 99% certian that the problem is in the top end of the motor, more-so in the valve train.

edit -- the dipstick was clean as a wistle, i let it run for a few mins after sitting for 2 days so the oil wouldn't run as fast as at OT so there was more oil on the stick, and then let it get to OT and still was clean with no shiny flakes of metal.
 

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Easiest thing to do is take your valve covers off and check the rocker arms. Make sure one of them hasn't come loose then. You can torque them down but make sure the cylinders aren't at TDC or you risk sending the valve into the piston. Also, when you check, the hydraulic tappets will bleed down, so just be aware of that when you are looking around.

I think your description of the squeal is throwing us off, you might have two seperate issues then. Possibly a bearing going out on the pulleys or soemthing for the squeak.
 

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Discussion Starter #8
Easiest thing to do is take your valve covers off and check the rocker arms. Make sure one of them hasn't come loose then. You can torque them down but make sure the cylinders aren't at TDC or you risk sending the valve into the piston. Also, when you check, the hydraulic tappets will bleed down, so just be aware of that when you are looking around.

I think your description of the squeal is throwing us off, you might have two seperate issues then. Possibly a bearing going out on the pulleys or soemthing for the squeak.
Well, i took a stethiscope (forgive my spelling) and the squeak is coming from the #1 cylinder location, again more so under the valve cover.

The truck goes tomarrow to the trans shop to fix another rotten egg and hopefully i can tear into it this weekend and figure out whats going on.

Thanks for the help guys!
 

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Squeak?

Not trying to be smart ass but I did not see anyone mention the fact that just maybe the spark plug is loose and chirping out around the threads? Just a thought to be checked out.
 

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Discussion Starter #10
Not trying to be smart ass but I did not see anyone mention the fact that just maybe the spark plug is loose and chirping out around the threads? Just a thought to be checked out.
The spark plug was loose whn i got it home that day, i tighted it back down but still did the same thing and you can still feel the vibration on the plug wire.

Possibly burnt the threads out around the plug? I however cannot feel any air coming from the plug shroud IIRC.

I will for sure check into it when i get it home wednesday from the trans shop. Thanks for the input!!!
 

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Shoo Shoo Retarded Flu !!
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Oil pressure is fine, however, after 2 30 min trips at hwy speeds, when i turned off on the side road, the oil pressure blipped to zero, check guages light poped on, then jumps right back up to normal.

But that was 2-3 weeks prior to this problem.

I'll dick with the oil & pan after the truck comes back from the trans shop.

Any other options on this?
bad rod bearing, went through it on my R/T
 
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