04chevy5.3

Ok I got a new truck last saturday. It was running real rough and throwing random misfire codes. I got that fixed(a couple of injecters were pluged up). It has 130,000 miles on it. I changed the oil and switched from penzoil to mobil 1. Last night as I was coming to a stop I noticed a knocking noise coming from the engine. So, I get out to check on it and sounds like the noise is coming from deep in the oil pan or in the back of the motor somewhere. Could going from penzoil to mobil 1 loosened something up like a rod bearing or something. I want a new motor anyways but was not planning on doing it this soon.

gmtechnician

just changing the oil alone will not cause a bearing to knock. The problem was probably there. good luck

hourang

iTrader: (6)

i sure hope you got a killer deal on the truck...

Whippled 496

iTrader: (4)

i have heard that going from dino oil to synthetic after 20k can have adverse effects on seals and things. It seams that the dino oil works its way into the engine differently than the synthetic will. I have heard of issues with oil leaks and things when switching, but never knocking. Your best bet is to use the dino oil exclusively if you have that many miles on it. Try switching back to regular oil and see what happens.

04chevy5.3

oh yea....it also threw a crank sensor code last night...im at work and i dont remember the exact code...im not even sure its coming from the motor...i paid 3500 for the truck so i think thats a pretty good deal

04chevy5.3

anyone got a 6.0 for sale

04chevy5.3

What else could be knocking...could it be something in the torque converter or at the flywheel?

BlackGMC

iTrader: (31)

I wonder if the old oil was a lot thicker or had a couple of oil treatments in it masking the knock? Try putting some oil treatment or switching to a thicker wait oil and see what happens....

04chevy5.3

ill change the oil today and see what happens... i bought the truck from my brother so i know it doesnt have any oil treatment in it

04chevy5.3

should i go back to penzoil? i really dont like to use it but if i have to to limp by til i can get a new motor i will.