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dom14
27th November 2015, 08:46 AM
Hi Guys,
I replaced the 30mm welch plug on the exhaust side of the block for the second time.(RB30 engine)
This time I did the job while taking time, and used Permatex Aviation liquid gasket.
I cleaned the welch plug hole and cleaned the edges with a soft sand paper as well.
Then I applied a little bit of gasket paste on the plug as well as the hole edges and left it for few minutes then
installed the plug.
I found out yesterday, it's leaking again.
It's leaking from the bottom end of the welch plug.
I used a socket to carefully hit the plug into the hole.
I used a slightly smaller socket so the crush plug won't have trouble crushing while going into the plug hole.
I did everything by the book, slowly. Yet, it's still leaking.
I'm wondering what to do now.
Should I leave it for a while and see if the leaking stops after a while?
Or should I redo it straightaway with a different kind of sealant paste?

I'm thinking,
1)Silicon gasket sealant
2)Epoxy
3)Loctite red

or a mixture of 2 and 3.

I could post a photo, but it won't show anything useful.


P.S. First welch plug replacement was leaking the same manner(no sealant), but after a month or so, leaking has slowed down. I think it got plugged by rust, 'cos I was using plain water at that time to flush the radiator and engine, before I was going to put coolant. Right now with the second welch plug with sealant, it's running on rust inhibitor+distilled water.
I didn't use antifreeze(will add it later).

billyj
27th November 2015, 04:44 PM
stag jointing compound, no substitute when it comes to welch plugs

dom14
27th November 2015, 06:35 PM
stag jointing compound, no substitute when it comes to welch plugs

Yeah, I guess I won't have a choice but using the best stuff, but can't find it nearby.
If I don't plug the hole tonight with epoxy & loctite thread locker, I'll find stag glue tomorrow and do it that way.

It's an absolute biatch to have to do this three times so far. :(

my third 256
27th November 2015, 06:54 PM
plumbing supplies is your best place

dom14
2nd December 2015, 12:03 PM
I did it with long curing Araldite & Loctite Red. Mostly Araldite, but added few droplets of Loctite along the edges of the hole & the plug.
Left it for three days. Filled it up with coolant yesterday and ran the engine to temperature. No leaks so far.
I reckon this time it's going to stay that way.

dom14
9th December 2015, 12:43 PM
It's going good now. No more leaks. :D

threedogs
9th December 2015, 04:45 PM
stag jointing compound, no substitute when it comes to welch plugs

X 2 on the Stagg ,ooi do they still sell this stuff

billyj
9th December 2015, 06:26 PM
im sure i saw it in bursons or repco when i was getting bits to build my 355 holden a few months back

dom14
11th December 2015, 03:18 PM
im sure i saw it in bursons or repco when i was getting bits to build my 355 holden a few months back

Fleabay Autobarn also have it.

http://www.ebay.com.au/itm/Stag-Jointing-Paste-200G-/321892815612?hash=item4af24e92fc:g:sVEAAOSwwbdWHWK Q