I have had two occasions that I found antifreeze in the bowl of the carburetor. It was suggested that I remove the intake manifold to see where the antifreeze is coming from. I found a small amount of antifreeze in the front intake port. Any suggestions or is the next step the removal of the head?
It could be a leaking head gasket or a crack in the block. You might check the torque on the head bolts first. If they're a little loose, tightening may fix it. Worth a try before pulling the head. If they are tight, start by pulling the head and #1 intake valve. A good cleaning will be needed before inspection. Tiny cracks will seep it they extend into the water jacket.
My bet is that you have a crack in the block that runs in one or both of the intake ports. Remove the intake manifold and clean out the ports and take a close look. If you can rig up a way to put a little pressure on the block. Block off the block and head going to the radiator and apply a few pounds of air pressure and watch for water coming out. I'm sure there are other ways, But I have done this on a few engines with some luck.
sounds like you have a crack in a valve seat.
Mike is correct, do all the testing and inspection you can before pulling the head. After the head is removed it may be harder to find a leak in the block.
You might try some KW block sealer before you tear everything apart.
Re-torque the head first. That's the easiest thing to do. Drain the carb to make sure it's clean of coolant. Use the car and check if it happens again. If it does pull the manifold and look for clues as to where it's coming from. Hopefully it'll show inside the manifold and narrow down the problem cylinder. Gives you a place to look. A that point it's pull the head and look for the possible crack. I wouldn't blindly pour sealant into the radiator without diagnosing the trouble first.
What year is your engine? I've heard that '26-27 blocks are famous for cracking.
The engine is a 1923.
Allan - Just a reference note if you need it; the new Vintage Ford has a few procedures listed that describe steps you can take to pressurize different areas for testing purposes. They are detailed in the article on overheating.
A leaky freeze plug...
Could be the head.
A look at your spark plugs might tell you which cylinder. If one plug is really clean and white, that's the problem cylinder.
Thank you for all your suggestions. I took the easiest suggestion; torque the head. I found that the head needed torquing and took the bolts to 45 ft-lbs. I then watched the intake port and did not see antifreeze for a couple of days. Then I saw a small amount in the intake port. I pulled the head (no gasket sealant was used) and checked for cracks. Did not find any. I removed the first two intake valves and saw what might be a crack, but wondered if what I was looking at is a parting line (not sure that is the right expression). Hopefully, you can see the line I am referring to in the uploaded photo. A friend check the flatness of the Z head and found it to be within 5 to 6 thousands.
I'm wondering what would be "thinner" than water? Here's the idea if nothing else is apparent: disconnect & plug the lower rad hose connection on the block then fill the block and let it sit while you look for the leak. Although I believe heat may be involved you
just might see some seepage if that line is really a crack. Kerosene or paint thinner perhaps?
I had a crack in the valve galley very similar to the area in this photo, i bought a JB weld product called Perm-O Seal, it is non metallic and doesn't mess up anything, it says it is organic and can be reused, when you drain the radiator etc, just put it back, it works great stopped my leak for eight years now. You can look it up at J B Weld.com.
Looks like a parting or mold line in the photo.
"I'm wondering what would be "thinner" than water?"
Water/anti-freeze mixture is.
Maybe it's just the fuzzy photo but it looks like your valve seat is in terrible condition as well as the surface of the block.
Can you post a clearer photo, not so close-up?
Also, why does the bottom of the intake part appear machined around the valve guide hole? Has guide bushing been installed?