95 Blazer engine noise

[wlsnoops]

95 Blazer 4.3L V-6
120,000 Miles

Went to the store the other day, about 2 miles away, and noticed a strange pecking noise coming from under the hood. No warning lights came on, oil pressure, temp guage fine.

Had to wait until the next morning to check things out. Started it up and white smoke came out the exhaust. After about 30 seconds, the pecking noise became progressively worse, so I shut it down.

Noticed what looked like water mixed with oil coming from under the engine. Checked dip stick for water. Looked good. No milky residue. Coolant level in radiator okay. Resevoir level empty.

The pecking noise sounds like it's coming from the bottom of the engine.

Where should I start checking? What test guages will I need?

Thanks.

[herkyhawki]

Look at water pump to see if leaking.
Remove belt and start engine for one minute. Is the noise gone? If so, the noise is one of the accessories, probably water pump.
If noise is there with belt off, it is an internal engine problem like a bad bearing.

[MT-2500]

Does not sound good.
As said pull belt and see if noise goes away.
If not disable one cylinder at a time and see if any cylinders affect the nosie.

Noise can travel.
Could be anything from a cracked flywheel to a rod or main bearing or piston or lifter noise.
Also I have had several with a piece of carbon on top of piston make a bad noise and also a bad PCM can do some strange things.
Before you throw a engine at it have a experiance tech/mechanic listen to or check it.
Good Luck
MT