Thread sealer or silicon?

[DANNY]

Pulling a motor apart noticed that they used black silicon and didn't use thread sealer for the head bolts. Is this better or equal to the white permatex stuff in the brown jar I always used? I'll be putting motor back together this weekend.

Thanks,
Danny

[dereksehi]

When we assemble them we use permatex #2 and haven't had any leaks. I prefer the permatex #2 over white Teflon as I've had the Teflon leak before and I would recommend against using silicone.

[Lizardracing]

Ive never used anything else so I don't have comparison. I keep doing what I know works.

[let-r-eat]

Why do you recommend against using silicone?

[dereksehi]

I recommend against silicone because most of the major gasket companies do and also silicone is hard setting unlike Teflon paste or permatex #2 and may start to cure before you are finished torquing the bolts and the seal could be broken on the next torque step.

[stockcar5]

I recommend against silicone because most of the major gasket companies do and also silicone is hard setting unlike Teflon paste or permatex #2 and may start to cure before you are finished torquing the bolts and the seal could be broken on the next torque step.

Gasket makers dont want you putting silicon on gaskets. this post is about head bolt threads. Silicon is fine.

[dereksehi]

You guys can use silicone on your head bolts but I won't use it on mine. I will either use permatex #2 or the older machinist I work with that's been doing it since 1971 uses silver anti-seize and that seems to work well also he doesn't like silicone either.

[connor]

Antiseize on head bolts is crazy never heard of that. It isn't made to seal water I have been using silicone for years never had a problem but use what you feel comfortable with.

[jamminjayman5]

I've never used anything but anti-seize and never had an issue.

[dirtplay18]

Always had good luck with the white prematex thread sealer, just don't over-apply. I also use red label moroso ceramic seal and straight water for the initial fill and warm-up cycle. Never had an issue.

[50j]

White Permatex here too, never a leak so far.

[NAYRBNYLF]

Permatex "right stuff " was told by ARP fasteners about ten year ago.

[Brian Gray]

T paist . been using it for years no issues.

[Brian Gray]

Silicone on bare metal will promote electrolysis. In a race motor that gets torn down frequently its a fine substitute and works well. But in an engine you want to last a few years its not the best compliment to your build.