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info on retorquing headbolts on 97 suburban


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sgrant
New User

Sep 17, 2008, 8:48 AM

Post #1 of 4 (2119 views)
info on retorquing headbolts on 97 suburban Sign In

I just replaced the heads (and bolts) on my 97 chevy suburban (5.7L, 180.000 miles) and when I was cleaning my torque wrench ( a few days later) I discovered the nut on the end of the handle was loose. I had already driven the car a few days and now I'm not confident about the actual torque I used on the head bolts. The instructions with the Felpro gasket kit stated that the bolts did not have to be retorqued, but I want to anyway. The method (in the shop manual) for torqueing the head bolts says to bring them all up to 22 ft-lbs and then tighten them an additional 55, 65, or 75 degrees (depending on bolt length). If I retorque each bolt individually (following the order listed in the manual) am I going to do more harm than good? Also, If the engine has already been run (less than 100 miles) am I wasting my time? It may be my imagination, but I think I can smell a hint of coolant in the exhaust. Any guidance is appreciated. Scott


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Sep 17, 2008, 9:28 AM

Post #2 of 4 (2116 views)
Re: info on retorquing headbolts on 97 suburban Sign In

Questions: Do you trust this torque wrench now? Can you compare it to another? What was the reason you were there to begin with?

You think you can smell anti-freeze now so chances are there's trouble. Are you sure the original trouble was just a gasket job and that, that alone should have solved a problem?

Guess: I'd go back and check if only to find out that in fact they are wrong. It may take another gasket to fix it again now as it could have been damaged in places that should have been tight enough to protect itself.

Bummer but I see no out but to go back,

T



Jeff Norfolk
Enthusiast
Jeff Norfolk profile image

Sep 17, 2008, 11:23 AM

Post #3 of 4 (2109 views)
Re: info on retorquing headbolts on 97 suburban Sign In

Just to add to what Tom said, you should probably redo it. Also in my experience these torque to yield bolt (which is the kind of head bolts you have) need to replaced each time they are removed in order to reach proper torque. Since a bolt stretches each time it is tightened, and the final step is to turn the bolt a certain amount rather than a certain torque, than correct tightness can not be certain with old bolts because of prior bolt stretch. You might be ok using the old bolts, but it is a lot of rework in this case to take a chance. Hope this helps.
Jeff


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Anonymous Poster

Sep 24, 2008, 4:39 AM

Post #4 of 4 (2031 views)
Re: info on retorquing headbolts on 97 suburban Sign In

Thanks Jeff and Tom for the advice. I went back and retorqued the bolts and that got rid of 90% of the smoke. They were new bolts, and since I'd only driven the car a few miles (less than 100) I took a chance on re-using them. After that, I did a ThermaGasket treatment (anything to avoid removing the heads again) and that eliminated the smoke completely. I've driven it for a week now and everything is normal. Thanks again for the help. SG

P.S. Jeff, Thanks for the education on "torque to yeild bolts". I still hate 'em (compared to normal bolts) but at least I know how they work.






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