GMC Repair: Knock or Ping in front of block, grude oil, gmc sonoma

Question
I recently purchased a 1989 GMC Sonoma with the 4.3 V6. I was intending on putting in a new engine, as they told me the engine was blown. After carefully examining the motor I decided to look into it I changed the Oil, it was setting up for 6 years. The mileage was 71500. Anyway the oil was like fresh grude oil I had to take something and stick into the oil pan finally poured kerosene through till it broke loose got it running. Runs great however has a knock in front of the block like a piston or ? The oil pressure is great 60 normal operating temp and 40 idle the knock seems to be louder after the truck has warmed up to normal and even louder under exceleration. I appreciate any info. you could supply.

Answer
Hi,William

Though i would need to hear the engine running to diagnose the noise,however if its a loud knock at idle and at speed it sounds like a worn rod bearing,you can attempt to run the engine and cancel each cyl,if the noise goes away or is very slight then its a worn piston wrist pin,if the noise doesnt change when you cancel the cyl then its a rod bearing or rod that has failed.

ED