Replacing heads on 2002 Avalanche. Purchased new bolts with gasket set. I have the torque specs, but cannot tighten to specs.

Completed step one which was all 11m bolts torqued to 22 ft. lbs (which is not very much).

Next step is to tighten all 11m bolts to 90 degrees. None of the bolts would tighten to 90 degrees. A couple got close, but some only tightened an additional 45 degrees.

Not only are they not going that 90 degrees, but they are supposed to each go an additional 90 degrees or 50 degrees for #9 and 10.

It is not for lack of strength or ability... these bolts just don't want to move. I am afraid I'm going to snap a socket. They are supposed to be TTY bolts, but don't seem to have any "stretch" in them.

Prior to installing, I cleaned out all of the bolt holes like I was supposed to, used compressed air to blow them out as well. If it was one or two bolts, i could see that perhaps the holes weren't properly cleaned... but every one of them is the same.

Is it possible the bolts are not TTY? The set appears to be correct... all bolts are the correct size, lengths, etc. They came with the fel pro gasket set, so I can't imagine they are the wrong ones.

Any help or experience with this would be greatly appreciated! Even with the seemingly heavy torque specs, it should not seem so tight that one would fear breaking tools or snaping bolts!

 

So how were the head gaskets?

Couldn't tell of failure??


https://chevroletforum.com/forum/ava...t-heads-66248/

How is your water pump? Is it leaking?

This is great for a midnight post here..

This is happenening on both sides? Are these new bolts/studs/nuts? Used?

Did you use any gasket stuff on the head bolts or everything went in dry?

Are you following Helm's manual specs? Or who is your source??

 

I guess in the overall scheme of things - 45 degrees isn't much!??!!!!

I couldn't find anything in my 1995 LT1 manual this late at night for replacing heads and bolt torque...

*sorry I'm a non-professional backyard hack who swapped out heads on an LT1 350 back in 1999.
definiitely didn't TTY anything....

 

No water pump leak. The head gaskets looked a little rough, but no "smoking gun" visible on gaskets or heads when they came off. Truck had all the symptoms of a bad gasket and/or head (steam from tailpipe, losing coolant, oil residue in coolant reservoir).

With all the write ups on those heads, I decided to swap them out when I had everything apart as to not take any chances.

So far, I have only attempted installing one side. I stopped when I couldn't torque the bolts to the proper spec. They are brand new bolts. They came with thread lock compound on them, otherwise they were dry. The chilton manual does not say to add any oil to them, but I was wondering if that is what I should have done anyway.

I guess that answers your other question too. I am using the chilton manual for specs which are identical to every other post and guidance for torque specs.

Of all things to get hung up on!

 

maybe try oem head bolts

 

Do you have the run the vehicle to temp then re-torque ?

 

have you compared threads and length of both with the old ones ? I know maybe a daft question but couldn't see you said it anywhere