258 Expansion plug replacement

[JZLAJeep]

Have the day off for Columbus day and decided to take on the leaking expansion club on the CJ-7. Bought Dorman expansion plug part number 567-017 which appears to have the "large" expansion plugs, but not the "small" plug that is leaking. I understand that I hit the top or bottom of the big plugs to turn them sideways and then pull them out with pliers, but how are these "small" plugs removed? And what do I replace them with?

 

 

 

[AZJeff]

Removal is usually done by drilling a hole in the plug and inserting a lag screw or similar into the drilled hole. 
 

Any decent auto machine shop can set you up with a replacement plug if you give them the ID of the hole in the block.

[75sv1]

Also, NAPA might have individual plugs for sale. 

[JZLAJeep]

I did get the old plugs out. Apparently the smaller plugs are 1" diameter. I bought Dorman 555-018 1" steel expansion plugs that are sold individually. The diameter is slightly larger than the plugs that came out however. That has me a bit worried, but I suppose they'll go in with enough pounding. 

 

I was glad the 1" plug was steel because the first punched through into the cooling jacket and had to fish it out with a magnet. Couldn't have done that with a brass plug. @AZJeff I didn't see your removal suggestion until I already had the plugs out, but that's a good idea.

 

Planning to delete the EGR while everything is apart.

 

I've since cleaned up the ports since I took this photo. They are clean and shiny now.

 

The old plugs. I punched through the rotten one that was leaking. That actually made it come out easier.

 

[derf]

One thing if you have to replace them again.  I don't remember the exact compound you use but a light coat of sealing compound on the mating surfaces before you drive them in can prevent leaks.

 

I had an engine rebuilt and a couple of the plugs leaked because the shop skipped the sealant.

[Eagle_SX4]

52 minutes ago, derf said:

One thing if you have to replace them again.  I don't remember the exact compound you use but a light coat of sealing compound on the mating surfaces before you drive them in can prevent leaks.

 

I had an engine rebuilt and a couple of the plugs leaked because the shop skipped the sealant.

I have used Permatex Form-A-Gasket No. 1 with great results in the past.

[JZLAJeep]

44 minutes ago, Eagle_SX4 said:

I have used Permatex Form-A-Gasket No. 1 with great results in the past.

I've seen some people recommend Permatex No. 1 and at least one other recommend gasket shellac. I don't know if it's just a preference for which to use. I suppose if they work, that's all that matters.

[JZLAJeep]

Got the 2" plugs in easy enough. I'm struggling with the 1" (allegedly) plugs however. The new plugs are slightly larger diameter than the old. If you look at the photo, the new plug peeks out from under the old plug. With the assistance of AI though, I've learned that Dorman sells 61/64" diameter plugs (Part #555-125) and 25 mm (0.984") diameter plugs (Part #555-097). Hopefully one of those works!

 

 

[MagicJames]

I recently did this on a 2.5, and if the plugs are even just 0.5mm larger than the ones I took out, they didn't seat properly for me. 

[JZLAJeep]

25 mm (0.984") diameter plugs (Dorman Part #555-097) were the answer. I understand Dorman 555-125 (61/64" Dia.) plugs have been discontinued.

 

[AnotherOldJeepGuy]

I often learn stuff here, today I am learning the existence of these plugs.  I have been hunting a coolant leak, perhaps I need to "expand" my search to these things.  Are the locations I have marked "?" also expansion plugs?