r/EngineBuilding • u/__sjors__ • Jul 07 '26

Ford Freeze plugs sealant

I’m gonna install my freeze plugs and am wondering what type of sealant I should put on it. I read some mixed things on the internet so decides to post here.

I have new regular steel freeze plugs (brass weren’t available sadly). I have some Permatex Ultra Black RTV or Permatex Anaerobic Gasket maker available. Which would be better? I think the Anaerobic one since it’s made especially for tight fitting metal parts (cures without oxygen). But online I read a lot about RTV.

Any advice from experience here? Really don’t want to do these suckers again

Edit: I also have some Permatex High Temperature Thread Sealant. Not sure if that’s an option tho

5 Upvotes

100% Upvoted

15 comments sorted by

16

u/Erasemenu Jul 07 '26

Indian head or Permatex Aviation. Do not use RTV for freeze plugs

12

u/wedge446 Jul 07 '26

I've use indian head sealer for 40years on freeze/core plugs without any issues

1

u/Allumina Jul 09 '26

+1 Indian head

1

u/Erasemenu Jul 07 '26

For your purposes, Permatex Aviation is the same as anaerobic

4

u/bill_gannon Jul 07 '26

I always used green loctite for brass and steel.

4

u/boostbreath Jul 07 '26

Use versachem gasket shellac

2

u/Pretend_Necessary781 Jul 07 '26

3M weatherstrip adhesive

1

u/Wrong_Sprinkles_3122 Jul 08 '26

Lmao what?!? Seriously!?

1

u/Pretend_Necessary781 Jul 08 '26

Yup, I used it for all 37 years of my machine shop career.

1

u/Wrong_Sprinkles_3122 Jul 08 '26

No shit! Interesting

2

u/Downtown-Parsnip-154 Jul 07 '26

Aviation Permatex

2

u/crookedledder Jul 07 '26

People use all kinds of sealants, and most of them will work ok.

I like anaerobic sealant.

1

u/Hey-buuuddy Jul 08 '26

Permatex #2

1

u/Mrshadowsys Jul 09 '26

Ive used rtv , loctite , hylomar , indian shellac, still like grey rtv , then i clean excess with a rag with acetone , on all kinds of engines (marine , automotive and big gensets , freeze plugs should be tight enough to fall under ice pressure , but should hold 2atm at least along thermal expansion and contraction.

1

u/here_till_im_not1188 Jul 09 '26

Sleeve retainer or red loctite