Leaky Welch plugs

[zoenryan]

Finally got the wifes Territiory back together after replacing the Welch plugs , thought you would like some pics.






Took a while to get them out and new ones back in. Dont know what has happened here , but a bit of web research leads me to speculate as follows.
1. coolent hasnt been changed for 4 years - so some corrosion evident. Old plugs were liberally covered in sealant which may have been shielding plugs from corrosion - those that were starting to rust were not too bad.
2. hole is unbeleiveable - looks like someone has taken a drill to it from the inside
3. Could be a defect in the metal - an inclusion, which set up its own electrolytic circuit once conditions were right.
4. Read somewhere that the plugs are designed to be sacrificial so that if electrolysis starts - they rot first before it attacks the block - bit like a sacrafical anode - dont know if this is correct, but If so coating them in sealant not a good idea as it would shield the current .
So - elected not to coat the new plugs on the exhaust side which are easy to get at and repllace and coated the ones under the inlet manifold which are more difficult.
Plugs can be changed with the motor in. there is lots of room with the manifolds off.

Used permatex no 3 to seal them and so far no sign of even a slight leak.

total cost less than $200 with new plugs from Repco. new manifold gaskets and new coolent.

So - CHANGE YOUR COOLENT every 2 years or so and use good stuff - I used Nulon which now has an inhibitor in it.