Coolant leaking around #8 head stud
 

I’ve been chasing the cause of a rough running engine. Went through the electrical/ignition system and carb. New points and coil. Then I took the head nut off of the #8 bolt and green antifreeze began oozing up around the bolt and running off the head. I’ve noticed a white smoke (or steam) around the exhaust manifold too. Am I looking at a head gasket problem?

Re: Coolant leaking around #8 head stud
 

Looks so.

Re: Coolant leaking around #8 head stud
 

Vincent, It appears your engine is sort of a fresh rebuild, maybe several years ago? I would be interested to see what type head gasket was used. There have been many posts about this on Ford Barn over the years. "Some" modern gaskets seem to have given up prematurely. I've been using the original type copper/asbestos type with no problems. You'll find pulling the head is usually a simple job.

Re: Coolant leaking around #8 head stud
 

This is why you never ever remove head nuts with coolant in the cooling system! You need to do more testing to check the head gasket for leaking. Overfill the radiator remove fan belt run engine looking for bubbles. Compression check differential compression check. Or I see antifreeze tear the engine down?

Re: Coolant leaking around #8 head stud
 

I would also drain the oil pan just in case the antifreeze got into the oil!

Re: Coolant leaking around #8 head stud
 

If you removed that nut just to remove the primary cable, a leak is common. Thats why i don't use that clamp. If it wasn't leaking before, I'd recommend tightening it and watching it. It'll probably be fine.

Re: Coolant leaking around #8 head stud
 

Before anything else, if you suspect a head gasket leak, do a compression test.

Re: Coolant leaking around #8 head stud
 

x2. Now that you've taken the nut off with coolant in the system, and the coolant has leaked out around the base of the stud, the gasket seal around that stud is ruined. It will never seal properly again even if you re-torque that stud. Time for a new head gasket. Don't bother with compression checks, just replace the gasket because if you torque it down and get a good reading now, the gasket is going to blow in the not to distant future.

Re: Coolant leaking around #8 head stud
 

Model A engines can develop problems when any head nut is removed. Murray Fahnestock did an article for the Restorer a long time ago how you can affect the compression by adjusting the head nuts. The #8 there is problematic due to the electro-lock clamp and the fact that is is at the narrow zone between #3 and #4 cylinder. If the head shows any sign of seepage or coolant leak then it's time for a new head gasket.

Re: Coolant leaking around #8 head stud
 

If that is an original style head gasket before you tear it apart you might try a retorque to see if there is improvement. Original style head gaskets have successfully been reused if not otherwise damaged.

Re: Coolant leaking around #8 head stud
 

Here is a simple mod you can do to avoid loosening the #8 head nut.

Re: Coolant leaking around #8 head stud
 

Taking the head off will give you a chance to inspect the cylinders and valves and the surfaces of the block and head. You can also look for cracks. Moving the pistons back and forth when they are at the top of the stroke will give you an indication of how much cylinder wear you have. Also inspect the studs and replace all if any are necked.

Use the Best brand graphite gasket and K&B copper spray gasket cement when you put the head back on. Make sure the head and block are absolutely clean with a final wipe of acetone. Do not use a wire wheel or sand paper to clean the block or you stand a chance of scoring the cylinders.