knocking noise

[joeythefixer]

I had an annoying problem. I had a knocking noise that was coming from the front of the motor. could not find the source for a long time and I didn't want to start replacing parts. I used a mechanics stethascope to narrow down the choices and eliminated all the accessories. finally decided to remove the serpentine belt because the noise seemed to be coming from the balancer. Of course my imagination went wild with a rod knock or bearing problem. As it turned out, the bolts that attached the main drive pulley were loose. tightened them up to spec and no more noise. I hope this is helpful.

[Drake_tr7]

Wow, that's a new one on me, but I'll damn sure remember it. Thanks Joe

[John Dancy]

Thanks for the knowledge.

[Thomas R. Smith]

Many years ago, I had a '69 Chevy Impala with the 350 cu in engine that did the exact same thing. And, yes, I can attest to the noise sounding just like a rod knocking. And, yes, it was a bitch to pin down, too. Once the bolts were torqued to specs, it never happened again. Hope you have the same results.

[gadget73]

I recently went through a knock on startup diagnosis with my S10. I thought it was the broken motor mount causing the problem. Turns out, the torque converter bolts had backed out a bit, and it was the bolts slopping around in the hole on the flexplate causing the noise. I removed them, added loctite and installed them to torque, no more noises.