The Stovebolt Site Forums The Shop Area Engine Shop Bolt fell off engine by oil line

Trucks been home a week and i wanted to clean off some
Of the engine as i was wiping a bolt fell off in my hand. Pic below. Go easy on me my Dad was the brains of this restoration when i started. He passed away so your the next best thing! What is this hole? I looked at diagrams maybe a drain? Its not leaking but what do i do next! Thank you! I circles the hole in my pic!

That appears to be the drain plug for the water jacket. Not surprised it isn’t leaking as they get plugged up with junk. Mine didn’t leak when I threaded it out.

Agreed, I have a petcock installed there. Might want to clean it out with a stiff wire (with the accompanying flow of coolant). I'd consider a good flush of the cooling system too.

Any idea how long the bolt was? Ill have to have it removed and replaced. I think i saw a petcock in one of the diagrams.

It is not a bolt.

It is a taper thread plug.

As Forty9 says above, install a petcock (tap) there it assist future maintenance.

The block is thin there, perhaps only 3/8" , so the plug will be short.

I used a straightened coat hanger to dig out mine. It was full of crud. I then pressure washed that hole to break it loose even more. I, however, was doing a full rebuild and hot tanked the block soon after. You probably don’t want that crap making its way into the water pump. Flush it. Lots.

Clean the hole out with a 20 gauge shotgun brush in a drill motor and chase the threads with a 1/4" pipe tap. Install a new pipe plug with a dab of Permatex #3 sealer on it and you're good to go for another 50-something years.
Jerry

Thanks for all the info so glad i have all of you! Someone put a bolt in the hole (pic attached) but ill work to get the right plug and get it cleaned out!!

I would suggest that there is no need to clean that out unless you want to drain the block. A plug with pipe threads is what you need.

A word of caution, I cracked a head on a 42' 216. the # 1. The temp gauge was not getting any water to it. For some reason the older 216's have this problem with flow if the water jacket is not flushed before starting up. A lot of folks didn't run anti freeze I suppose. You probably need to ask the folks here, the 235, 261's have larger jackets. Doc.