Can I get away with removing one headbolt at a time then running a tap on a long 1/4 drive extension to chase the block threads
then replacing the headbolt to proper torque?
i ask this question cause the threads were not chased on this headgasket job and the original torqueing had some discrepancies
the engine has only been warmed up after headgasket job
it was not driven
it has been sitting for a few weeks
Headbolt torque redo question
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Headbolt torque redo question
Love those Tercell 4x4 wagons but they sure suffer from road noise.
- helipilot77
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Re: Headbolt torque redo question
You might be able to get away with it but it is risky. How will you ensure that you get the crud out of the holes? A vacuum and a long brush might work?
. / TOYOTA
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- Petros
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Re: Headbolt torque redo question
If you think there is a high risk of the head gasket failing because of uneven torque, you might as well give it a try. This is what I would do: back off all the bolts to about 16 to 20 ft-lbs in the same sequence as you torque them. do not back them all the way off. Than take one out at a time, also in the same sequence, chase the treads, and clean the threads, clean off the bolts and use thread lube, torque it back to 20 ft-lbs. ONce all are replaced than make two passes bringing them all up to spec torque.
I have done something similar once and did not have a problem, still driving on it 2 years later in fact.
When you clean it try and get one of the spray nozzels with a lone metal tube extension so you can get it all the way to the bottom to blow it out. That way it will blow debris out, not down into it. You can also use a small metal tube with a normal spray nozzle. Use lots of solvent and a small wire bottle brush or a gun barrel brush (you can get cheap ones in most auto parts stores) to clean it out, and than blow out with solvent several times.
After you drive it for a few days I would retorque it, back off each head bolt about 1/8 of a turn and torque up to factory spec, again in the correct sequence as the FSM.
Should work. if not, likely you would have had to replace the head gasket again soon anyway.
I have done something similar once and did not have a problem, still driving on it 2 years later in fact.
When you clean it try and get one of the spray nozzels with a lone metal tube extension so you can get it all the way to the bottom to blow it out. That way it will blow debris out, not down into it. You can also use a small metal tube with a normal spray nozzle. Use lots of solvent and a small wire bottle brush or a gun barrel brush (you can get cheap ones in most auto parts stores) to clean it out, and than blow out with solvent several times.
After you drive it for a few days I would retorque it, back off each head bolt about 1/8 of a turn and torque up to factory spec, again in the correct sequence as the FSM.
Should work. if not, likely you would have had to replace the head gasket again soon anyway.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
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- helipilot77
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Re: Headbolt torque redo question
That sounds like a good plan Petros. I would agree with that as likely the best solution.
. / TOYOTA
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Re: Headbolt torque redo question
For extra safety I would drain the cooling system if you'll be pulling any bolts out all of the way.
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Re: Headbolt torque redo question
FOLOWUP
i did pull the headbolts and run a tap in the holes
i backed off all head bolts about a quarter turn (in reverse torque order)
then removed one at a time in torque order and tapped the hole and reinstalled and retorqued the bolt to 46lbs
i heated the square end of a 10 x 1.25 tap to soften the metal and drilled a 1/8 dia hole thru it
did same to female end of 6 inch long 1/4 drive socket extension
pinned then together and used std tap holder "T" handle to chase threads in block
its been 9 months and so far so good
i did pull the headbolts and run a tap in the holes
i backed off all head bolts about a quarter turn (in reverse torque order)
then removed one at a time in torque order and tapped the hole and reinstalled and retorqued the bolt to 46lbs
i heated the square end of a 10 x 1.25 tap to soften the metal and drilled a 1/8 dia hole thru it
did same to female end of 6 inch long 1/4 drive socket extension
pinned then together and used std tap holder "T" handle to chase threads in block
its been 9 months and so far so good
Love those Tercell 4x4 wagons but they sure suffer from road noise.