Header Nuts

[ap5512]

Quick question for those of you who replaced the stock nuts when installing aftermarket headers. I'm going to be re-installing the OFH this weekend but wanted to replace the stock nuts since the last time they kept coming loose. I know they are 14mm but wanted to know anyone knows exactly what kind they are? I'm not sure you can just grab any 14mm ones and put them on.

As always, thanks for your help!

[bababooey]

cant say what kind per se but i do know there different thread pitches for nuts & bolts can exist. example- the amount of threads per linear inch and the angle of the valleys/peaks can change. if not matching it will strip something if you brute force it.

[ap5512]

correct - I tried looking on subaru OEM parts to see if it's something i can get at the dearlership but not sure I found anything substantial. I'm hoping someone can chime in and let me know exactly. also, the bottom are flat and have ridges for locking maybe?

[JDLAutoDesign]

Use a M10 x 1.25 metal lock nut and you won't have any issues

[ap5512]

Thank you @JDLAutoDesign ! I'll go to the auto/hardware store to see what they have.

[mav1178]

If you are using brand new stock nuts, you won't have an issue.

If you reuse stock nuts, they'll back out.

-alex

[Amputechture]

Had the same problem, get one of those jokers with nylon/elastic so they won't back out and you'll be worry free.

[Fizz]

Originally Posted by Amputechture

Had the same problem, get one of those jokers with nylon/elastic so they won't back out and you'll be worry free.

Not sure about using nylon lock nuts on hot exhaust though....they might melt? When I installed my turbo manifold I used these titanium lock nuts instead. Holding strong so far and no leaks.

https://www.probolt-australia.com/ti...et-of-6-1.html

[steve99]

never had a problem with stock nuts comming loose

use new gaskets and also put some high temp anti seize on nuts and studs, work nut over threads couple of times and then wipe off excess antizeize and any rust or dirt.

apply some fresh antiseize then torque up nuts to specified torque

start car and let it run for a few minutes then retorque


if you just torque up dirty or rusty nuts most of the torque is used to overcome the rust and dirts on threads, then once they heat up they will come loose.

if their nice and free with a bit of antiseize then your actually applying the correct torque and they should be fine.

[ap5512]

The original nuts kept on coming loose the first time i installed the header and i could tell right away because the noise was different each time i drove. I used anti-seize after i got tired of retightening every weekend but this time im thinking of getting new nuts and using anti-seize (after cleaning everything). Thanks for the help guys!