Engine: Leaking core plug (Champion 6)

[nvonada]

I went to take the car out last weekend and found most of the coolant on the floor. Turns out the core (freeze) plug on the back of the block is leaking. That creates two problems. First of all I put this plug in. At the time I felt like I was putting it in backwards but that was the way the old plug was in both my engine and the parts engine. I now suspect both engines were wrong to start with. This is what I am talking about:

So my question is should this plug be an outie or an innie?

The second problem is getting at the plug. There is almost an inch between the firewall and the back of the block. I am hoping I can remove the rear crossmember and drop the back of the engine far enough to get to the plug through the access panel in the transmission tunnel. See the pictures below. I hope that works or the engine is coming out again.

[rockne10]

Start it in a convex position. Pressing it in expands its circumference and produces the seal.

[RadioRoy]

There is an easier way to replace this plug while the engine is still in place in the car. This is how I did it some 35 years ago on a 51 Champion and it hasn't leaked since. You don't state what year your car is, or even if it is a truck, but this should still work.

You will need a long jobbers drill bit, an angled Allen wrench slightly smaller than the drill bit diameter, and a long thin flat punch, slightly smaller than the drill bit diameter.

1. Buy a jobbers length drill bit. Around 1/4" will do, and the drill bit needs to be a foot long or longer.

2. remove the front floor mat

3. Locate the position of the freeze plug and make a mark in the inside of the firewall. This is the toughest part to do. Try for the center of the freeze plug. The closer you get to the center, the better it will work.

4. With the long drill bit, from inside the car, drill through the firewall and through the old freeze plug

5. From under the hood, hook the short end of the Allen wrench in the freeze plug hole and pop the freeze plug out

6. Clean the block, coat the new freeze plug with Permatex or something suitable, and set it in place

7. From inside the car, take the long punch and set the freeze plug.

8. put the carpet back in

[tbirdtbird]

I like the above procedure for removal. They make a type of freeze plug which you tighten with a wrench to expand it , need about a 9/16 wrench, they make a very good seal. I would still apply Permatex #2 (Dorman makes'em i think, and I think they have been mentioned on here before.) You prolly have enough room to get at the nut on the plug.

For traditional convex plugs, most ppl whack'em too hard and they end up concave, which then shrinks the diam. You want to tap them just enough that they are FLAT. And the bigger diam. the drift you can use on them the better. a small 1/4 punch you'll have trouble getting a good seal. There may be other sources but www.McMaster.com has very long bits. They are my fall-back for anything weird. You can calll 24/7 and you have the item within 3 days

[nvonada]

I could drill the firewall. The engine is so close a regular drill bit would probably reach. I just hate the thought of cutting though my firewall for something as stupid as this. There is also some sort of fiber insulation glued to the firewall that could be asbestos-based. I try to avoid messing with it.

I bought a regular 1 1/2" welch plug last night and I will try the engine dropping approach. My FLAPS has the expanding Dorman plug too so if this does not work that will be my fallback. I think all I need to do is drop the driveshaft, disconnect the exhaust pipe, put a jack under the belll housing, remove the rear crossmember, and lower the engine about two inches. Thanks for the advice!

Nathan

[nvonada]

I finally got time and good weather at the same time yesterday and dropped the back of the engine. Looks like I found the leak:

And it is this kind of freeze plug:

If I had remembered that I probably could have fixed the leak by tapping the plug a little tighter. Too late now. How best do I install a plug like this? Obviously I got it wrong the first time.

Thanks,
Nathan

[K-Hawk]

Roy, great advise. I have drilled holes in fender wells to get sparks plugs out of big blocks.

[RadioRoy]

Nathan, I invented this procedure after looking at a huge 4 X 6 hole someone cut into another car's firewall to replace the same freeze plug. To my way of thinking, a 1/4" drill hole is much less obnoxious than a huge flap of bent sheet metal. I was too lazy to drop the engine.

K-Hawk, Thanks. I once had a Henry-J with a flat head four. To adjust the valves, you removed the right front wheel, removed a panel from the inner fender, and adjusted the valves from the wheel well. It was interesting having the brake drum in your chest while doing the work.

Additionally, my 65 Skylark shop manual tells how to take a large compass, make a few arcs, and mark a point on the inner fender well. Then drill a hole to get at one of the heater core bolts.