: hole in block?

11-09-12, 12:00 PM
Any idea what this is? The hole is the bolt closest to the oil pan by the freeze plug. We were cleaning the engine and I think it was packed with dirt and whatever and it started dripping coolant. We stuck a short bolt in but I don't think it's threaded much if at all. Any ideas on what it is and what to do? It's still oozing. Safe to maybe add some sealer to the bolt? I believe this is a 73 472 that I'm dropping in my 78. Hole is on the passenger side


The Ape Man
11-09-12, 09:08 PM
Looks like a coolant drain plug hole. IIRC they take a fine thread plumbing type bolt.

11-10-12, 08:41 AM
It has a tapered thread. It takes pipe threaded bolt. Use teflon thread dope or teflon tape when replacing the plug.

11-10-12, 05:02 PM
If I remember correctly, it needs a 1/8 NPT pipe plug. There should be one on the other side of the block also.....

The Ape Man
11-11-12, 10:13 AM
It should be here somewhere:


11-12-12, 06:52 PM
A 1/8 inch pipe plug can be found at a building supply, like Home Depot or Lowes.