Unknown engine noise help

[78C10BigTen]

Ok so this noise has been in this engine most of the time ive had it, this vid seems to be its loudest so far. It sounds rotational to me but idk. Its at the front of the engine, can anyone help me nail this down?? Its super friggin annoying!!!!

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[Blue Ox]

Sounds like a bearing on something is on it's way out.

Best diagnostic technique I can think of is a long screwdriver against the accessories like the alternator, A/C compressor, water pump etc. and against your ear. You'll hear it distinctly when you're on the bad component.

***Obviously, (I hope) be careful not to get it in the belts or fan or whatever moving parts.

 

[78C10BigTen]

I think i may pull all the belts off and start it for a minute to isolate engine or acc.

 

[Snoots]

My money's on an alternator bearing.

 

[78C10BigTen]

My money's on an alternator bearing.

That would suck... its not that old

 

[dvdswan]

Could be the water pump. But being that loud you could pull the belts off and spin each item. Another thought if its been doing this for a long time even before replacing the alt, you could have sagging motor mounts and the fan is hitting the fan shroud.

 

[78C10BigTen]

Could be the water pump. But being that loud you could pull the belts off and spin each item. Another thought if its been doing this for a long time even before replacing the alt, you could have sagging motor mounts and the fan is hitting the fan shroud.

Another overlooked possibility

 

[78C10BigTen]

Could be the water pump. But being that loud you could pull the belts off and spin each item. Another thought if its been doing this for a long time even before replacing the alt, you could have sagging motor mounts and the fan is hitting the fan shroud.

Quick visual inspection its not the fan.

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[QBuff02]

Quick visual inspection its not the fan.

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Is the engine fan on backwards or am I seeing things?

 

[78C10BigTen]

Is the engine fan on backwards or am I seeing things?

Ive never messed with it... always been that way. Truck never goes past 210 so cant be too bad

 

[Charlie]

Sounds like a bearing on something is on it's way out.

Best diagnostic technique I can think of is a long screwdriver against the accessories like the alternator, A/C compressor, water pump etc. and against your ear. You'll hear it distinctly when you're on the bad component.

***Obviously, (I hope) be careful not to get it in the belts or fan or whatever moving parts.

This is what I would try myself. Easier than removing belts to investigate. If no satisfying results, then belt removal would be next. Alternator bearings can be very loud. A wooden yardstick is good to use also. Good luck

 

[dvdswan]

Is the engine fan on backwards or am I seeing things?

It depends on if the vehicle had a serpentine belt or v-belt. Serp belts rotate the w/p in the other direction. It looks correct just a smaller fan. I thought there was like a 1/2" clearance to the edge of the fan shroud. Looks like he has an inch or so.

Aside from that, it may be a 4wd issue, but doesn't the crank pulley come close to the engine crossmember. I maybe thinking of another type of vehicle though. Your noise is a grinding noise so I'm trying to think outside the box other than a bearing.

 

[78C10BigTen]

So as i sit here in the running truck on my break at work, it made a liar outta me. Its not doing it now. Maybe it needs to be fully warm to expose itself...

 

[82sbshortbed]

So as i sit here in the running truck on my break at work, it made a liar outta me. Its not doing it now. Maybe it needs to be fully warm to expose itself...

Problem solved. Lol

Just kidding. Maybe the bearings need to wa rm up before they start making noise.

 

[HotRodPC]

Another cheap Harbor Freight tool everyone needs. I got mine on sale for either $1.99 or $2.99. I don't recall now, but just get one. It'll replace the old long screwdriver trick and you don't have to worry about taking your eyes off the belts and pullys when you turn your head to put the handle to your ear. Just get one.

https://www.harborfreight.com/mechanics-stethoscope-63691.html?_br_psugg_q=stethoscope

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