Core Plugs - Go in dry or with sealant?

[htiek]

Hi Folks,

 

I've had one of the cylinder head core plugs rot through (just above the exhaust manifold). It's been a devil of a job getting it out with only limited access through the rear wheel ach, but finally had success last night.

I've got the new plug but I've read various advice on fitting them on the 'net. Some seem to advocate that they are put in dry, other's say to use Hylomar or similar.

Does anyone know the official story?

 

Thanks,

Keith

[jonwat]

In his book Lotus Twin Cam Engine, Miles Wilkins recommends Wellseal, a non-hardening jointing compound, when fitting core plugs.

[johnpwalsh]

Yep I agree, I previously used red Hermatite as suggested by a good mechanic friend of mine and they sealed and stuck without a problem and that was on an old Volvo 122S with the B10 engine which tended to run a bit hot. Just make sure you have them square on when fitting.

 

John.

[htiek]

Thanks Guys,

Luckily I bought a few spare plugs as it took 3 attempts (and about as many weeks) to finally get it in square and water-tight. Access through the wheel arch is not good!.

 

-Keith

[Mike6]

Well done, a difficult job - probably have cost a fortune to get it done in a garage.

[Sir Paolo]

I used Loctite 572 (liner sealant) on mine

[Vulcan Grey]

I would use a Loctite retaining compound.

 

They have one specifically for core plugs.

https://tds.us.henkel.com//NA/UT/HNAUTTDS.nsf/web/40C0BFA8BA8391A2882571870000D809/$File/540-EN.pdf

 

 

I actually used some Loctite retaining compound (green) to seal the new water pump spigot in my head.

I removed the old 2 piece (steel and aluminum) pressed in spigot and made a new one from aluminum.

 

I froze the spigot with dry ice, and put the head in the oven, ad did a shrink fit with the loctite to make sure it was sealed!

 

Replaced this