Mechanics

GMC C1500 ENGINE PROBLEM

2013 GMC C1500 • 300 miles

Is the serpentine belt tensioner supposed to run smoothly in place, or is the tensioner designed to "jump" a little bit? Also, as the belt comes off the tensioner pulley, the belt is vibrating (kind of like a guitar string does); I remember that the serpentine belt on my old '06 Sierra pickup ran just as smooth as silk all the way around, with no vibrations in it at all.
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GH496bbt
December 22, 2012.




MAKIN' ANY RACKET?

REMOVE THE BELT AND TURN THE PULLEYS---DO THEY ALL SPIN FREELY? (EXCEPTION THE CRANKSHAFT PULLEY OR DAMPER---IT ONLY TURNS WHEN THE ENGINE DOES!)

WIGGLE THEM--THEY SHOULD ONLY TURN---NO WIGGLE SIDEWAYS

ARE ANY OBVIOUSLY ROTATING OUT OF ROUND?---LOOK FOR THIS, BEFORE THE BELT IS REMOVED---WITH ENGINE RUNNING (I'VE SEEN PEOPLE USE THE PULLEYS FOR LEVERS WHILE PERFORMING ANOTHER FIX!

NOW GO TO THE TENSIONER--DOES THE TENSIONER PULLEY PASS THE PREVIOUS TESTS. WHAT ABOUT PULLING OR PUSHING THE TENSIONER'S ARM TOWARDS OR AWAY FROM THE ENGINE? IT SHOULD ONLY "TENSION" NOT HAVE SIDEWAYS PLAY!

MY 1ST PIC DEMONSTRATES A TENSIONER "PULLEY" HAVING GONE BAD---THIS ONE WAS PLASTIC---SOMEHOW THE BELT REMAINED ON FOR QUITE SOME TIME. THE "GREAT AIRBORNE RANGER IN THE SKY" WATCHES OUT AND TAKES CARE OF FOLKS LIKE THISHE LEAVES ME BATTLING THESE KINDA TRIBULATIONS! (HELPS ME IN THE END!)

EVEN BEING NEW---THINGS DO GET GLITCHES STRAIGHT OFF OF THE ASSEMBLY LINE---MAYBE SOMETHING NOT SEATED WELL WAS "TIGHTENED DOWN" ANYWAY--OR A BOLT WAS CROSS THREADED

BEING THIS NEW----I'D LET "THEM" CHECK IT OUT!

KEEP US POSTED ON PROGRESS

THE MEDIC
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CJ MEDEVAC
Dec 22, 2012.
Yes, it's the racket from under the hood that first drew my attention. As soon as I lifted the hood it was apparent where the noise was coming from. (From inside the truck, the noise sounded like unlubricated tappets; Yikes! I was actually glad to see what it really was.)

I should have told you from the start which motor I have. I decided to go with a 6 Cyl. This time, so I have a 4.3L V-6. As you look into the engine compartment, the tensioner is on the far left (passenger side). The belt travels straight up for about 9 inches and then goes over the alternator pulley. (This where the belt is vibrating like a guitar string; between the tensioner and the alternator.)

I ran through your checklist. I took a 3/8" breaker bar, unloaded the tensioner, and slipped the belt off. I went around to each pulley. They were all in good shape; no sideways wiggle; they spun freely.

Then I went to the tensioner, pulled it toward the radiator, pushed it back toward the engine block; back and forth many times with a lot of force. It was OK there. Then I got a 15MM socket and took the tensioner off the engine. I made the pulley spin as fast as I could with the palm of my hand; it ran real smooth. I checked for sideways wiggle; no problem there. I put the tensioner back on and the bolt ran in OK so there was no cross-threading. (I don't have a Chilton's for it yet, but I figured 32 ft. Lbs. Of torque would be alright.) I put the belt back on and the problem is still there.

Right now I'm thinking that the tensioner has an internal defectthat the spring-loading mechanism has some play in it allowing the tensioner to jump up and down.

Thank you very much for your expert guidance, and with your guidance I believe I've been able to whittle it down to the real problemyou can't have too much knowledge when going up against a service writer when you're seeking Warranty Repairs ('nuff said).

Man, I just love the picture of your WWII Airborne Ranger Jeep. The tiresThe embossed Willys logo under the windowWOW!


Tiny
GH496bbt
Dec 23, 2012.
Is your belt in good condition? As far as the tensioner, I have seen many of them shake while the engine was running. It seems the only way to get rid of that problem is to replace it. Although they are holding tension on the belt, there isn't enough.

He does have a nice Willys doesn't he. He totally rebuilt it. Not bad for a guy from SC


KEEP US POSTED ON WHAT YOU FIND OR IF YOU TAKE IT BACK........TO GET A JEEP!

HERE'S SOME MORE OF MY AWESOME ADVICE!

http://www.2carpros.com/questions/2001-ford-f-150-grinding-noise-upon-light-braking

THEY SOMETIMES DON'T UNDERSTAND RURAL ROUTE FIXIN'!........WAITIN' ON GOOD NEWS FROM 'EM!

http://www.2carpros.com/questions/1999-ford-taurus-whines-starts-had-new-power-steering-pump-amp-pullies

THANKS FOR THE COMPLIMENTS!

RANGERS LEAD THE WAY!

THE MEDIC



CJ MEDEVAC
Dec 24, 2012.

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