Mechanics

CHEVY LOUD KNOCKING, LOSS OF POWER, CAN'T FIND

1999 Chevrolet Venture

Engine Mechanical problem
1999 Chevy Venture 6 cyl Wheel Drive Type unknown Automatic 113000 miles

My van was running fine for the most part and then one day I could hear a faint flapping sound while driving. I assumed I had something caught in the tires. This lasted for about a week and then the flapping sound turned into a popping which grew louder as I drove. The louder the sound got the less power she had until we were topping out at about 30mph and it sounded like large rocks popping around in the engine. It also seemed not to " shift" as we drove. The mechanics listen to it and said I need a new engine. We pulled it apart and the rockers were good, the piston rods are fine, and there are no flakes in the engine oil to suggest an issue with the cam and cam bearings. In short we can't find any reason for the problem. Where else should I be looking. My gut tells me its a cheaper problem than an engine replacement. But I need some where to start. Thanks
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Ppnj4
March 21, 2008.



Did it sound like a back fire noise? Or did it sound like metal to metal?

Tiny
Rhall77
Mar 24, 2008.
It sounds exactly like giant rocks popping around inside my engine. Not a knocking and not a backfire. Metal to metal would be more appropriate.

Tiny
Ppnj4
Mar 24, 2008.
Did it sound like a ping noise?

Tiny
Rhall77
Mar 25, 2008.
If I had to use a different analogy I would say the sound makes me imagine the pistons hitting something metal really hard. It is not a ping. It started out very similiar to the sound a card on your bicycle tire spokes makes, then became quite quickly a sound resembling rocks the size of a golf ball popping around a metal popcorn popper. It makes this rock popcorn sound from the time you start it and gets louder/faster as you step on the gas.

Tiny
Ppnj4
Mar 25, 2008.
You said everything in the engine is tight right? Did you look at the transmission, lie the converter and see if anything was loose there?

Tiny
Rhall77
Mar 25, 2008.