cracked head?

I put plugs in my X headed 408 and the one plug I had to use a breaker bar to remove. See pic., The other 7 were all fine so I guess I have a cracked head in this cylinder. I didn't notice any water in the oil or excess water out of the exhaust though the coolant level was down. I ran a compression test and it was ok for now but I would assume if I continue to run it its just a matter of time before that changes. My question is has anyone ever successfully fixed a cracked head or is it time for a replacement?

Looks like maybe something leaking from the outside ? heater hose ? dripping in that area.

You haven't proven that you have a leak. I agree with CSK. The rust above the spark plug threads seems to indicate the water is coming from above the head.

- EM

I can't imagine where. I thought/hoped the same and wish that was the case but this is the driver side. The car is garaged never gets wet and the heater hose are on the pass side E-body.
I think I'm going to pull the exhaust manifold and see if there is evidence of rust in the port.

The porcelain and electrode of that plug look way different than the others in the picture.

agreed, it looks like corrosion up close. I assume its getting some water in the chamber. The rust on the barrel is a little deceiving in this picture. The other plugs have some too just not in this picture.

With that much rust on the plug threads, the plug can't be grounding woth a darn, I would expect to see the electrode messed up. That plug wasn't far from being one with the head. Gene

A little Never seize and the plugs are much easier to get out.

Can you shine a little light into that cylinder and see how 'clean' the piston top is?

May sound weird, but I had a bad pinhole spot in the exhast cross-over on my '596 SB castings...it managed to leak enough water at operating temperature over about 5 mins of runtime to completely leave the top nearly spotless. Make no mistake, it was tiny enough of a pinhole to push enough water to just turn into steam but far from a hydrulic lock, enough to clean things right up. By the time I got it home I could tell me coolant level was down a bit.

Being able to fix a cracked head depends entirely on the location of the crack and the type of head. It's certainly not something most can fix themselves, and I've seen even experienced machine shops do nothing but make the problem worse.

I'd consider getting one of the inexpensive bore-scopes that are available and taking a peek through the spark plug hole. I have this one and the resolution is pretty darn good. If the piston is clean you are probably getting water in. If not, there is something else going. Might want to try a leak down test?

https://www.amazon.com/dp/B01MYTHWK...a1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

maybe get a radiator pressure checker and put some pressure on cooling system while the engine is off and check to see if you have any leaks

This will let you know right away.

All great suggestions. I going to do the leak down but it may be time for a bore scope anyway. Didn't know they had them for Smart phones now, That's cool thanks, for the link. I think I'm going to be looking for some heads in the end.

Which cylinder is it? If one of the corners, it may be coming through the intake gaskets. Ive seen that happen on other brands but their ports are closer together than an motor.

I'm still wondering why we're going directly from symptoms to a cracked head. No chance it's an intake/head gasket problem? Just seems more likely to me...

Its number three so it's one in. I didn't figure it would be an intake leak at that location it seems it would have been an end cylinder as stated above. These are original X heads that had some old port work done. I'm more of a big block guy but have heard that the X castings were somewhat crack prone. I need to do the leak down an try an see the piston top