Have an engine knock in a 1999 Chevy Blazer 4.3L Vortec Engine. Knocking on the inside of the engine on the left side towards the front near the alternator. Thought it was a stuck lifter but a motor flush and oil change didn't fix the issue. When it started the knocking in the engine, noticed the oil gauge would drop to 20 while driving and then to 0 when coming to a stop and back up again when accelerating. Stopped driving it once it started. Thinking that a rod is the issue.

Is it possible to replace just rods or other parts without having to replace the entire engine? Or what other possible issues could it be?

 

You might have spun some bearings. Thats what happened to mine, my oil pressure would be at 0 at a stop and go up to 20 when moving and when you rev the engine you can here a knock so i pulled my engine and tore it down and the crankshaft was shot with the bearings

 

Depending on how bad it is you may be fine with just replacing the bearings and having the crank made circular again. if the crank is beyond repair then youre better off looking for a used low mileage engine.

 

I bought a reman crank from autozone for 188

 

If its tht bad off you can look forward to changing or tearing apart your engineto fix it.The crank is probaly toast along with the bearings