Freeze plug leaking in my 47

[Bob Richards 13906]

I have a freeze plug (block plug?) slowly leaking on the drivers side rear of my 47 346. Does any body reccomend a product to help stop the leak? Is there a product that will also work in the system to condition the block against corrosion? Thanks, Bob

[Bill Gauch]

By blocking corrosion, I assume you mean in the coolant system. I also am assuming that your leak is also coolant. Coolant additives to stop leaks are evil. I dont know what they would do in an old engine, but I know they gum things up pretty severely in a late model one. If you mix the standard 50-50 of antifreeze and water, you should have all the corrosion protection you need. That should probably be flushed and refilled every 3-5 years to ensure protection. Actually, if you use a modern antifreeze, the manufacturers explicitly recommend against any additional additives. As for your leak, I would think you could replace the freeze plugs. They have probably corroded enough to cause the leak.

[Paul Flykt CLC # 18899]

When changing coolant be sure to use distilled water. Eliminating the minerals in tap water is well the cost of distilled.

[Doug Houston]

If youre do-it-yourselfer, I recommend replacing all of the welsh plugs (core plugs, if you prefer). Its messy, but there has had to be rust either in the center area of the plug, or probably at the edge. Youll be using 1 1/4 inch DISH type plugs. the block should be as dry as possible when you install them, and Ive always put a bead of permatex around the periphery of the new plug before upsetting it.

NOW, before putting in the new plugs, check for silt buildup at the rear of the water jacket. You can feel it with a finger poking in there. I spent a couple of hours one day on our inclined driveway, flushing out the mud from the water jacket. After I was done, there was no dirt whatsoever in that block. Youd be amazed at how much crap acumulates over the years. Your cooling will be much better after doing it.

[Rhino 21150]

If you have just a pinhole leak and only need a temporary fix until you can do a proper job, do this. Put a small sheet metal screw through the hole with a little silicone rubber on the back of the screw head. It will hold for a couple of months. Then it will cause the plug to fall out. That should buy enough time to locate and procure the parts.

[Bruce Reynolds # 18992]

Plus, when you go to purchase the replacement plugs, buy only Brass ones.   Then you will never have to replace them again.

Steel replacements never seem to last as long as the originals.

Bruce,
The Tassie Devil(le),
60 CDV

[Herman clc#19416]

I am not so sure the diameter given to you as 1 1/4 inch is correct having just replaced all in a 48 block and they were
1-47/64 so be sure you check before going out to get them even so they are very cheap. Installing them is no picnic but it can be done with a ball-pene hammer hitting the disk in the center of the disk, cup side into motor

For what ir is worth

Herman
6267X

[John Washburn]

Bob,

I agree, replacement is the best idea. Using brass  core plugs is best.

Or for a quick fix Dorman makes a quick seal replacement (as do others), which is rubber that goes into the hole in the block, and is then expanded by tighten the nut on the metal face plate. This is not the same size as the core plug since the core plug fits on the outside and this replacement fits in the hole into the block.

The one I am looking at (which I think is for my 56 cad) fits a hole 1 1/8 to 1 1/4, the core plug for the 56 is 1 13/16 so you can see the difference.

Anyway, just another option. Most Napa or good parts joints should be able to help (or try truck parts suppliers).

Good Luck

John Washburn
CLC #1067