Hey everyone, I am working on a 2000 civic EX D16Y8 head and pulled the core plugs to help clean out the upper coolant jackets (lots of junk in the coolant system due to a small but long term exhaust leak in the head gasket which kinda broke down some of the coolant hoses). I am getting close to reassembly and I can't find a spec on what sealant to use on the 2 core plugs under the cam shaft nor their torque spec. There was something on the threads (sealant or threadlocker) when I removed the plugs and I used an impact to remove the plugs. I was kind of surprised there were not crush washers/gaskets on the plugs. Also I can't find the plugs mentioned in the service manual. They aren't even shown in the explosion diagram on the head, at least on my manual, and I don't see them listed as a part you can order. I am guessing I want a medium or higher strength thread locker that doesn't react or loose strength with oil and glycol that also acts as a high temp pressure sealant. I have searched around and found some specific threadlockers (listed below) but most are special order. I was also kind of thinking about HondaBond HT or Ultra Flange Sealant (08718-0004 or 08718-0003)? Other engines (also aluminum heads) where I have pulled core plugs, the manuals listed 32 ft*lbs but those had crush washers but does not mention a sealant so I am not sure if that factors in wet threads. You all have any thoughts on this? Thanks!

Loctite makes a few specific formulas but they are all super expensive; Loctite 540 (aka 120541) or 962 Loctite 540 TDS , Loctite 962 TDS I have read somewhere that Ford uses Loctite 262 on some of their core plugs Loctite 262 TDS (Permatex's cross reference lists Loctite Threadlocker 262 as an equivalent to 26240 Permatex. Permatex cross reference)

Permatex 26240 / 19962 is advertised as a "Cup/Core Plug Sealant Retaining Compound" on their product page and easy to purchase on line, so I am leaning towards that. Oddly the TDS doesn't mention core plugs and the TDS is not easy to find. Permatex 26240 & 19962 TDS

Vibra-TITE 550 (Core Plug Sealant Retaining Compound) specifically mentions non-threaded. Vibra-TITE 550 TDS.

Hernon 928 (Cup/Core Plug Sealant) looks hard to purchase. Hernon 928 TDS.

 

Hondabond would be my vote.