Question : head bolts

[snowandgmc]

I'm rebuilding the top end of my 3.4 in my family van, in short the head gasket blew. both heads were replaced. heres my question i got 3 different instructions what to do with the head bolts in regards to thread sealant. one says to apply thread sealant and put in engine and do the usual torque and torque angle thing, one other says to put oil on threads on top of the sealant (doesnt say if it should be applied while sealant is dry/wet) and the other instruction (from book) doesnt say anything about sealant or oil on threads..... any help would be apprecaited.

btw kewl website!!!!

[3400-95-Modified]

I've never used sealant OR oil... so I think you should be fine doing it dry.

Wait for someone else to confirm that... BUT you should be replacing the bolts with new ones, you did that right?

[Superdave]

always use new bolts.. i always apply some loctite red to them just incase... never any oil.

[3400-95-Modified]

There's your answer... Dave's a Jedi Master at this stuff... LMAO

[Z26-T]

Use new bolts of course, the tensil strength decreases after you remove them because they stretch when being torqued, then when you de-torque them it weakens the bolt. So chances are that since they've been weakened, when you torque it they may break.

I would never use loctite... It kinda sucks when the bolt breaks in the block and you have to drill them out... And usually have to have a machine shop do it, unless you have the proper J-tools to helicoil it . The majority of the engine builders I know use a LIQUID teflon, that is if it's a wet hole. But personally I would just put them in without anything on them. Just go and buy new head bolts from a gm dealer. Usually if GM wants anything on the bolt, loctite etc. They'll put it on the bolt themselves. Also just checked GM Service Info and they don't say anything about using any sort of sealer on the bolts. So just go buy new ones and put them in.

[Z26-T]

There's your answer... Dave's a Jedi Master at this stuff... LMAO

Guess Dave has never broken head bolts while taking them out . They really suck to drill out , even with the J tools...

[snowandgmc]

of course its new bolts afterall want to do the job right the first time ha! i went ahead and used the thread sealant becuz the bolt holes are wet (even after blowing it out multiple times etc) but thanks for all the info! will keep posting if i run into any problems (hope not)

[bszopi]

I've always dipped them in oil before installing. Never used any thread sealant.

[ForcedFirebird]

Clean the threads with a chaser or tap, and apply a little oil to the bottom of the head of the bolt (right under the hex head only, not on threads), especially if the heads are used.

As far as re-using head bolts, I have reused them one time on many occasions, never had a gasket go on factory type rebuilds, but it is cheap insurance. My turbo 3.1 even had the main cap bolts re-used on them

everyone does things different, but in short, install the bolts dry since there is no fluid penetration on the head bolts.

[jonbourg]

Go with new bolts and put them in dry. Make sure the threads are clean and the holes are dry. I sprayed mine with WD40 and used lots of QTips. Blowing out with compressed air is also a good idea.

[pocket-rocket]

The paper that came with a set of Fel-Pro head bolts I used said not to dip them in oil, but coat the threads with a light layer and put some under the head of the bolt where it contacts the cylinder head. I've done dipped, dry, and reused head bolts and never had one fail yet... Key word, "yet" *knocks on wood*.

[Superdave]

Guess Dave has never broken head bolts while taking them out . They really suck to drill out , even with the J tools...

Nope.. i've taken out plenty too.. always with the impact gun on low.

i took apart a quad 4 with over 200K miles a few weeks ago, headbolts zipped right out. I've also never had a problem with loctite on them. I use loctite red on everything in my engine, headbolts, LIM bolts, rocker bolts, flywheel bolts, pressure plate bolts, mains and rod bolts, etc...


i can see why people add oil though, that does sound like a good idea.

[ForcedFirebird]

If you break a head bolt you are doing something way wrong, lol. Using long breaker bars at the JY even, I haven't broken a head bolt - I have split a few sockets, though.

One set of head bolts I keep with my engine hoist and has picked up many of engines, after they were used twice.

In the shop, I also use an impact for removal.

[Z26-T]

I never break a head bolt loose with a impact gun. Always with a breaker bar... So i'm guessing I used too much torque breaking them loose? .

In the dealer, at GM training school all say to use breaker bar when breaking them loose. Using the impact gun fatigues the bolt and can make it break easier. Everyone at the drag track, from the little 8 second guys like me, to the 4.5 second passes of the top fuel guys, we all use breaker bars to break it loose then use a gun to zip it out. But my engine cost only 30k, and theirs more.

Gm doesn't say to use anything on them, so I wouldn't. To coat them in oil was an oldsmobile thing back in the early 80s.