wrote: 97 Chevy S10 117k mi
I am the original owner. I change oil every 3000 miles. It runs just as it always has; no performance problems.
After I had the rear seals replaced I noticed a slight rattle from the rear of the engine when the starter first kicked. And I could hear the rattle during acceleration (like a jar of marbles bouncing around inside). It has become louder but still happens starting the truck & only when accelerating. I had it checked at the dealer and the mechanic said I need a new engine. He listed the causes:
Rod Loose Knob crank Low end rattle rear engine
I will have another mechanic check it out. Any thoughts? _______________________________________________________
"Knob crank" could have meant "Knock crank".
A worn crank bearing will knock when started and knock during acceleration, but get quieter when there is no acceleration. A bad rod bearing will knock when there is no acceleration and get quiet under acceleration. A knock sounds like a hammer rapidly thumping the engine block.
Some loose hardware rattles and jingles under vibration or torque, such as exhaust system parts. Rattles like marbles in a jar could be a failing bearing in a water pump or some other belt-driven accessory. A rattle like a can of gravel could be a sticking fan belt.
Having another mechanic check it out is a good idea. I think you should also go back to the first mechanic and ask him to explain what the thinks is the problem and why.
Good luck.
Rodan.