Inliners International Forums General Discussion MOPAR Freeze Plug Leaks?

Hi, has anyone on this forum ever had a freeze plug start leaking at the rear engine plug.
I have an antifreeze leak (very slow, discovered it leaking into the bottom of the bellhousing pan.
The trans is out right now, I can either pull the engine up and out, or repair it in the car, I have the large floor pan unbolted right now.
This Saturday, myself and a buddy, me green, he greener, will attempt to repair the leak. The car is a 47 Chrysler Coupe with a 1951 Canadian Doge long block flattie 218 and dry clutch and 3 spd trans.
The engine has had the side freeze plugs replaced, when I pulled the water distribution tube and the whole block was flushed.
Just trying to find out if the back freeze plug leaking is common, or what else it might be............47 man

47 coupe,

Confucius say: Rear Freeze plug leak because it hardest one to get to!

Seriously, if it's an original freeze plug (also called Core plug), 60 years is not a bad service life.

When you get the old plug out, clean the core hole in the block really well, before attempting to install a new one. I've always used a liberal swab of Permatex number 3 to ensure a good seal of core plugs. Worked for me since about '56!

If the core plug you're installing is the cup-type, you can use a socket and extension that will fit inside the cup flange then, holding it squarely against the hole, drive it in evenly.

If the plug is a expanding type, fit it into the hole, then expand it by hitting it dead center with a brass drift of about 3/4". One good whack with a one pound hammer should dimple it, causing it to expand and lock into the hole.

With good antifreeze in your cooling system, the new core plug should out-last you!

Once you've installed it like Dennis said, 'pressure test' (4-7#) the system to be sure.

If It's okay, then you can put the trans & all that back in etc.

Good luck.

Hi all, pulled the clutch, flywheel, bellhousing, the freeze plug was leaking, it was brass, and not rusted out. Cleaned up the area, even though I flushed the block, replaced freeze plugs, pulled water tube, there was a half-pint of crud in the hole,in the back of the block. I rodded it out cleaned it suctioned out what was there, flushing on my garage floor was not an option.
I reinstalled a 1" 5/8 freeze plug, with silicone adhesive, gave it a good whack in the center, the plug went in a tight fit, so I sure hope it's set in enough. The clutch and disc, need rebuilding, the flywheeel needs to be machined. Not a pleasant job to do, sure hope my work holds out, the flywheel, was a real beach to get out. Today filled the cooling system, after 10 hours no sign of leaking, "touch wood". Will have the 9 and 1/4 clutch disc and pressure plate rebuilt, the flywheel will also be machined, hopefully that ends this problem, I was also lucky enough to buy an NOS release bearing and sleeve locally for $25................Fred