TTY Head bolts

[NDIrish147]

I have a quick question that i cant find an answer to. I have an 01 nissan altima with a head gasket that went out. I have a new head gasket and new head bolts but when i torque down the new bolts i have one that will not hold torque. If i replace that bolt do i need to loosen and re-torque all of them in sequence or can i just re-torque that one bolt? thanks for any help!

 

[Trav]

Assuming you haven't fired the engine. Just replace it as its not holding torque anyway.
Do not loosen the rest, the bolts are already stretched.

TTY bolts are usually torqued by degrees for final tightening not with torque wrench.
Do not disturb the ones already installed and torqued properly, they will stretch even more the second try.

 

[NDIrish147]

I did the final torque by turning 90 degrees but the one bolt didnt seem to be strong so i checked the torque on it and it wouldnt hold 50ft/lbs the others were holding more than that

 

[NDIrish147]

I was just worried that because this bolt was the second one in the sequence that i would have to redo all of them

 

[bdcardinal]

I would be worried about the hole that bolt threads into if it is not holding tightness.

 

[NDIrish147]

I know it is not the hole.. i cant tell the bolt has stretched

 

[Trav]

No problem doing this. TTY bolts act like a spring, normal click type torque wrench values are meaningless past the initial reading eg torque to 50nm then an additional 90 degrees.

Edit: Check the length against a new bolt. If its the same you may have forgot the initial torque, you may have a bad bolt (doubtful) or the threads might be duff as bdcarinal said.

 

[NDIrish147]

thanks for all of the help!!

 

[Kestas]

At this point you can remove the bolt and inspect it, and check if it has necked. If necked, then you've likely found the problem. If not neecked and the threads look good, then you'll have to suspect the threads in the hole have yielded. This would earn a helicoil job.

 

[The_Eric]

All this is assuming that you've cleaned all the gunk out and there's no oil or coolant in the holes. Liquids in the bottom of a bolt hole make weird things happen.