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Chevrolet Repair/knock coming from motor

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Question
Hello and thank you for your time.  I have a 98 chevy 2500 5.7ch ltr. My problem is. Frustrating at best to say least i was changing my neighbors pcm out when finished i flashed it and found they a c.a.s.e.
Was needed to be preformed. During the test the motor started to knock so immediately stop the test and
Realized. The knock was coming from bottom end of the motor. Then remove the oil pan to inspect number 1,2,5,7 connecting rod bearing were spun so replaced changed out rod bearings but did not check out main bearings i only gave them a quick look. Put back together motor then ran fine no knocking in motor this time we went to do a crank shaft relearn drivabilty test before able to begin the test it start to knock again so attempted the test four times with no results. So replace crankshaft positioning sensor started the truck and now its knocking loud then before loud enough to make pause and think.it might blow have not done anything since

Answer
GOOD DAY MARILEE, WELL THERE COULD BE A FEW THINGS GOING ON HERE..YOU SAY THAT YOU REPLACED THE ROD BEARINGS BUT WERE THE CRANK JOURNALS OK ??? DID YOU PLASTIC GAUGE THEM ?? IT IS VERY POSSIBLE THAT THE CRANK JOURNALS ARE BAD OR SCORED AND THIS DESTROYED YOUR NEW ROD BEARINGS REAL FAST LIKE...THE OTHER POSSIBILITY IS IF THE MAINS WERE GOING BAD, THE OIL PRESSURE WAS GETTING VERY LOW WHICH WOULD TAKE OUT A ROD BEARING AS WELL. IN ANY CASE THIS ENGINE IS GOING TO NEED TO COME OUT AND GET IT REBUILD....I HOPE YOUR BUDDY DOES NOT THINK THIS IS YOUR FAULT BECAUSE YOU OVER REVVED THE ENG AT IDLE LIKE THIS TO RELEARN THE TIMING..I REMEMBER THE FIRST TIME I DID THE RELEARN I COULD NOT BELIEVE THAT YOU HAD TO TAKE THE ENGINE AT SUCH HIGH RPM FROM IDLE WITH NO LOAD ON IT TO RELEARN IT !!!  I THOUGHT FOR SURE I WOULD HAVE RODS COMING THROUGH THE BLOCK.. GOOD LUCK TO YOU,,,TOM.

Chevrolet Repair

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TOM SHEETS

Expertise

PLEASE READ ALL OF THIS BEFORE ASKING ANY QUESTIONS. IF THIS CHEVY SECTION IS MAXED OUT.YOU CAN REACH ME IN THE OLDS/BUICK SECTION. Will answer questions from 6:00am to 10:00pm all days [EST][[[ NO DIESEL OR PAINT QUESTIONS]]] will answer all 1965 to present QUESTIONS ON ALL GM'S on mechanics of these cars. Keep in mind i am not there in person i am going on what you are telling me !! PLEASE IF ASKING A QUESTION GIVE ME AS MUCH INFO AS POSSIBLE. THE MORE THE BETTER. SUCH AS YEAR,MAKE,MODEL,ENGINE SIZE. THIS WILL HELP ME HELP YOU. I will not be able to answer all questions because of some situations that i would really need to be there and see things for myself,such as electrical issues. In many cases i would need wiring diagrams. I can also give you an estimate on what the cost would be at our repair shop as an idea to help you. Keep in mind that my answer is ONLY MY ADVICE,ck with your mechanic as well.. >> THANK YOU, TOM..

Experience

I have been a ASE certified master mechanic for over 30 years and certified IN ALL 8 CATEGORIES,[engine repair,engine performance,auto trans,manual trans,clutches,steering and suspension,brakes,electrical systems,heating and air/cond. I am also a state CERTIFIED inspector for over 30 years. I do computer work [pcm]fault codes,pcm flashing,state inspection monitor readiness,repairs on exhaust,fuel service,[injection and carburetor,] charging system problems, running issues,alignments,frame problems,tire balance,struts and of course standard and anti-lock brakes.

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nys state auto repair industry and ase group.

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N/A

Education/Credentials
high school,4 years of tech school,and many many hours of auto training with many gm classes and aftermarket training classes..

Awards and Honors
ASE MASTER TECH CERTIFIED IN ALL 8 CATEGORIES.NYS INSP LICENSE AND A/C CERTIFIED

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MANY CUSTOMERS IN OUR BUSY SHOP.

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