2001 S-10 Extreme crankshaft noise 4.3 Vortec

[Blazing95]

2001 4.3 s-10 extreme
46,000 miles
I cannot figure this one out need your input.
After firing the motor up cold or hot the noise comes from the crank.
Originally thought a rod was broken- did compression test on all cylinders
perfect 200 psi on each cylinder-that was not it-rest assure.

Took serpentine belt of and turned the crank by hand-it sounds like a spring is being tightened up. pulley is in good shape rubber is good and the crank pulley does not slip nothing is loose.

Put everything back together and the noise is still their fired it up hot/cold
noise does not increase as rpm goes up nor does it go away.
Suggestions-?

[Schrade]

Originally Posted by Blazing95

2001 4.3 s-10 extreme
46,000 miles
I cannot figure this one out need your input.
After firing the motor up cold or hot the noise comes from the crank.
Originally thought a rod was broken- did compression test on all cylinders
perfect 200 psi on each cylinder-that was not it-rest assure.

Took serpentine belt of and turned the crank by hand-it sounds like a spring is being tightened up. pulley is in good shape rubber is good and the crank pulley does not slip nothing is loose.

Put everything back together and the noise is still their fired it up hot/cold
noise does not increase as rpm goes up nor does it go away.
Suggestions-?

Acorns in the fan blower???

What kind of noise is this? Hiss? Knock? Squeal? Hum? Doorbell?

Need clues dude!

[MT-2500]

Most engine noises change with RPM's.
Any check engine lights?
Does it do it in or out of gear?

[Blazing95]

Originally Posted by cbec1999

Acorns in the fan blower???

What kind of noise is this? Hiss? Knock? Squeal? Hum? Doorbell?

Need clues dude!

Acorns in the blower-? Cmon Next it will be Lice in the carpet lol
I know it sounds crazy but it sounds like a toy gun winding up a spring. On hot or cold start up it sounds as if something is dragging pulley to pulley but i took off the serpentine and manual turned the crank thus hearing the drag-Its Loud
never have i seen or heard this noise. It does not effect the driving of the truck speed, accelaration, stopping etc..Here's another way to describe it
Sounds like the flywheel is loose (Its Not) and after you shut it off it sounds like a loose metal part dragging,clanking like the connecting rod is broken (its not either). The pitch is a constant does not speed up or slow down.
Just turn the radio louder-? Done that too. What am I missing-?
BTW the doorbell works just fine. Clues-?Input-? Suggestions-? Thoughts-?

[Blazing95]

MT 2500 its been awhile good to see you still plugging away-Thanks
The noise does not increase with speed or slowing-No check engine nor anything in memory truck runs great gas milage is poor but i know their is fuel pressure problem. Still have to work on that but alot posts have helped me tremendously- Not a major problem yet-?

[Schrade]

Originally Posted by MT-2500

Most engine noises change with RPM's.

That's what I was getting at with fan blower / acorns. Everything about the motor increases with the rpm's.

You say pitch is constant, but also 'spring winding up'.

I have NO clue.

Pull the spark plugs, and rotate by hand again like you said you did before.

So it did make the sound as it ran, and also as you turned it by hand (or close)?

[MT-2500]

Originally Posted by Blazing95

MT 2500 its been awhile good to see you still plugging away-Thanks
The noise does not increase with speed or slowing-No check engine nor anything in memory truck runs great gas mileage is poor but i know their is fuel pressure problem. Still have to work on that but a lot posts have helped me tremendously- Not a major problem yet-?

You are welcome.
Try to pinpoint th noise.

A good listening device or a trained mechanics ear may help.
Good Luck

[Blazing95]

Originally Posted by cbec1999

That's what I was getting at with fan blower / acorns. Everything about the motor increases with the rpm's.

You say pitch is constant, but also 'spring winding up'.

I have NO clue.

Pull the spark plugs, and rotate by hand again like you said you did before.

So it did make the sound as it ran, and also as you turned it by hand (or close)?

Just having some fun..
Definetly pitch is constant when running does not increase with rpm's
When plugs pulled and hand rotated it sounded like a spring winding up at maximum. Yes it made the same sound obviously faster at 1500 rpm even driving it it was a constant sound- Its killing me. It goes next week to the professional I'll keep you posted- maybe it gremlins nearing halloween-?

[Blazing95]

Originally Posted by MT-2500

You are welcome.
Try to pinpoint th noise.

A good listening device or a trained mechanics ear may help.
Good Luck

Noise is pinpointed at the turn of the crank running or by hand.
It goes to the professional next week I'll post results
Stay Tuned.

Following up for us gear heads the strange never heard noise in the crank area sounding like a spring is exactly what it is. The return spring in the STARTER is kicking out the solenoid drive gear and dragging on the flywheel- I have learned something new today and wanted to post so I can sleep better tonight. Also the fuel pump is on it's way out I kind of allready knew that but wanted it confirmed. Thanks to all for feed back.
I now have a busy schedule to complete the above. GM gotta love em.

[Blazing95]

Originally Posted by Blazing95

Noise is pinpointed at the turn of the crank running or by hand.
It goes to the professional next week I'll post results
Stay Tuned.

Following up for us gear heads the strange never heard noise in the crank area sounding like a spring is exactly what it is. The return spring in the STARTER is kicking out the solenoid drive gear and dragging on the flywheel- I have learned something new today and wanted to post so I can sleep better tonight. Also the fuel pump is on it's way out I kind of allready knew that but wanted it confirmed. Thanks to all for feed back.
I now have a busy schedule to complete the above. GM gotta love em.

See the answer to the strange noise on the crank or I thought so..