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Chevrolet Repair/timing chain failure

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Question
hi.i have a 2003 gmc sonoma with 91k miles (bought it new).timing chain has broken.interference or non interference engine-everywhere i check i find a different answer.was going about 45 mph when it broke,kind of coasting,not on the gas hard.what are the chances of valve damage?so far i have heard 50/50 from different mechanics.no one seems to know what they are talking about.last mechanic i talked with wants to replace chain,gears and tensioner and see if it runs.what is your opinion on doing this?

Answer
HI JEFF, I AM GOING WITH YOUR LAST MECHANIC..WE HAVE SEEN JUST LIKE YOU WERE TOLD 50-50 ON THIS..HOWEVER IF YOU WANT TO KNOW BEFORE YOU DO A TIMING CHAIN,REMOVE THE VALVE COVERS AND
REMOVE EACH ROCKER ARM FROM THE VALVES AND DO WHAT IS CALLED A CYLINDER LEAK DOWN TEST..WHEN THE VALVES ARE CLOSED PER EACH CYLINDER YOU ARE CHECKING YOU PUSH AIR INTO IT AND CK FOR A LEAK EITHER IN THE EXHAUST OR INTAKE..IF NO LEAK IS PRESENT BY AIR DROPPING DOWN ON THE MACHINE OR YOU DO NOT HEAR ANY AIR ESCAPING IN THE INTAKE OR EXHAUST THEN THE VALVES ARE FULLY SEATED AND NOT BENT. BUT WITH THAT BEING SAID THIS TAKES SOME TIME TO DO,,MOST TECHS FEEL IT IS FASTER TO CHANCE TEARING DOWN THE FRONT OF THE ENGINE AND PUTTING A NEW CHAIN AND GEARS AND SEE IF IT FIRES..HOPE THIS HELPS YOU AND GOOD LUCK,,,TOM.

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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.

Organizations
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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