The Ford Barn

Piet · 04-15-2025, 01:23 PM

Hi,

I have a leaking head bolt. What can I do about it? The only thing to do is to put a new head gasket?

JayJay · 04-15-2025, 01:35 PM

So that water may be coming from either, or both, of two places.

1. As you already deduced, leaking head gasket.
2. From the water jacket under the stud, seeping up the shaft. Although I believe that bolt hole is normally blind (not connected to the water jacket underneath), over the years some enthusiastic mechanic may have "chased" these threads with a tap and punched through the bottom of the hole.

Repairs:

1. New head gasket, paying close attention to head torquing sequence to keep that tight.
2. While you have the head off, remove that stud and reinstall it with Permatex on the lower threads.

You could, I suppose, try removing that stud without pulling the head and gasket and reinstalling it. I use jam nuts to do this. But if those studs have been in place for a while they are likely not going to come out without a fight. Even so, you may end up having to replace the head gasket anyhow.

nkaminar · 04-15-2025, 01:54 PM

Are you getting steam out the exhaust pipe? Is there water in the oil so that it looks like a chocolate milkshake? Are you loosing compression in one or more cylinders? Has the carbon been blown out of one or more cylinders? Are you finding oil in the radiator or bubbles? Does an exhaust gas analyzer indicate exhaust gas in the radiator?

If you answered yes to any of these questions then you need a new head gasket. If not then you could probably get by with some gasket sealer under the nut. (I recently discovered Right Stuff gasket sealer that seems to do a good job, but the surfaces have to be cleaned of oil or other contaminates using acetone.)

Before you pull the head, you may want to re torque the head to 55 foot-pounds and see if that solves the leak. Do that on a cold engine.

The water in the coolant mixture will clean the carbon out of any cylinder where it is present.

Ruth · 04-15-2025, 02:01 PM

A club members AA truck was leaking there. Truck ran good, no signs of a blown head gasket. So we pulled the stud, splapped some shmuck on it and reinstalled. Still running to this day.

JayJay · 04-15-2025, 02:06 PM

Quote:

Originally Posted by Ruth

A club members AA truck was leaking there. Truck ran good, no signs of a blown head gasket. So we pulled the stud, splapped some shmuck on it and reinstalled. Still running to this day.

Probably goes without saying but... if you choose this route, be sure to drain the coolant first.

Joe K · 04-15-2025, 03:14 PM

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Quote:

Originally Posted by Ruth

A club members AA truck was leaking there. Truck ran good, no signs of a blown head gasket. So we pulled the stud, splapped some shmuck on it and reinstalled. Still running to this day.

This would be where I go first. Permatex No. 2

A stud puller will remove the stud with an impact wrench. You'll be putting the jaw on the thread to use this - but you'll still be able to put the nut on and torque it home afterwards.

Joe K

Mulletwagon · 04-15-2025, 03:49 PM

This is a common Model A issue and the school solution in published Model A maintenance books is to put aluminuzed stop leak in the cooling system. I had the exact same presentation three years ago. I went the stop leak route and the head bolts have been dry ever since. Recommend trying the stop leak routine before going through the new head gasket drill. The reason the headbolts sometime leak is they ARE NOT bolts, but instead, studs retained by nuts. Unless the threads and nuts are gubered with sealant during head installation, a minor leak past the nut is possible. Be sure and tell us how this caper ends. Good Luck.

Synchro909 · 04-15-2025, 05:23 PM

I suspect the hole under that stud has been @#$ed up by some ham fisted yobbo sometime. That allows the coolant to get past the thread and up to the top of the head. If you had the head off, I'd recommend a dab of goo on the thread and put it back. With head in place, a little radiator stop leak should do it.
I think a blown head gasket is unlikely.

Big hammer · 04-15-2025, 06:51 PM

That stud is below the nut, could have been pushed through the block, now coolant traveling up past the nut. X-3 on trying cooling system stop leak

ThirstyThirty · 04-16-2025, 12:44 AM

I was recently introduced to this product by a friend with a lot of dealership level repair service experience. I had not heard of it, but he swears by it. He had just picked up an underbelly Kubota mower, diesel, small.... 3 cyl... and it got hot in about 20 mins running. put this in radiator, warmed up engine for a bit... and went to work. Now stays cool. "Radiator?", I asked... "No, pretty sure head gasket....", he said.

Bob Bidonde · 04-16-2025, 07:23 AM

This slide may help you.

katy · 04-16-2025, 09:56 AM

Have you tried re-torquing the head nuts? From the look of the paint on the head it suggests some recent work on the engine.

Ruth · 04-16-2025, 10:32 AM

Quote:

Originally Posted by ThirstyThirty

I was recently introduced to this product by a friend with a lot of dealership level repair service experience. I had not heard of it, but he swears by it. He had just picked up an underbelly Kubota mower, diesel, small.... 3 cyl... and it got hot in about 20 mins running. put this in radiator, warmed up engine for a bit... and went to work. Now stays cool. "Radiator?", I asked... "No, pretty sure head gasket....", he said.

I was just reading an article about stop leak products. The consensus was from testing and interviewing manufacturers is the all stop leak product are designed for pressurized systems. They state it needs pressure to push the stop leak material in the holes.

So it may not work in a ModelA.

David in San Antonio · 04-16-2025, 01:34 PM

“….slapped some shmuck on it and reinstalled.”
I’m guessing shmuck is a generic term for sealant?

Piet · 04-17-2025, 05:17 AM

thanks everyone!! I'm going to try sealant first, if this doesn't work, I can always change the gasket.

Toppic can be closed.

nkaminar · 04-17-2025, 06:07 AM

Piet, Do not change the gasket unless it is leaking. Re torque the nuts to 55 foot-pounds. The leak at the stud is not a head gasket leak. See post #3.

ThirstyThirty · 04-17-2025, 09:17 PM

Quote:

Originally Posted by Piet

thanks everyone!! I'm going to try sealant first, if this doesn't work, I can always change the gasket.
Topic can be closed.

talked it over with my friend this morning over a cup of

/fone. we both agree on characteristics of a pressure system and one that is not. in any event, no doubt a retorque is worth the effort... i certainly would start there.

but, imo... doubt that will stop it!

Good Luck with the project! anxious to see how this thread ends!

Phil Brown · 04-18-2025, 12:06 PM

I would retorque the head first
Try your favorite brand of stop leak if retourque did not stop it
If still leaking try to get the stud out to add some sealant to the bottom threads of the stud
If the stud is stuck,..... you got a head start on pulling the head off

Most times stop leak will fix it

04-15-2025, 01:35 PM	#2
JayJay Senior Member Join Date: Jan 2020 Location: SF Bay Area Posts: 2,104	Re: leaking head bolt So that water may be coming from either, or both, of two places. 1. As you already deduced, leaking head gasket. 2. From the water jacket under the stud, seeping up the shaft. Although I believe that bolt hole is normally blind (not connected to the water jacket underneath), over the years some enthusiastic mechanic may have "chased" these threads with a tap and punched through the bottom of the hole. Repairs: 1. New head gasket, paying close attention to head torquing sequence to keep that tight. 2. While you have the head off, remove that stud and reinstall it with Permatex on the lower threads. You could, I suppose, try removing that stud without pulling the head and gasket and reinstalling it. I use jam nuts to do this. But if those studs have been in place for a while they are likely not going to come out without a fight. Even so, you may end up having to replace the head gasket anyhow. __________________ JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan It isn't a defect, it's a feature!

04-15-2025, 02:01 PM	#4
Ruth Senior Member Join Date: May 2016 Location: Glide, Oregon Posts: 1,441	Re: leaking head bolt A club members AA truck was leaking there. Truck ran good, no signs of a blown head gasket. So we pulled the stud, splapped some shmuck on it and reinstalled. Still running to this day. __________________ Ruth "Sometimes you really DO need to read the whole thread"

04-15-2025, 03:49 PM	#7
Mulletwagon Senior Member Join Date: Jan 2019 Location: Florida Panhandle Posts: 626	Re: leaking head bolt This is a common Model A issue and the school solution in published Model A maintenance books is to put aluminuzed stop leak in the cooling system. I had the exact same presentation three years ago. I went the stop leak route and the head bolts have been dry ever since. Recommend trying the stop leak routine before going through the new head gasket drill. The reason the headbolts sometime leak is they ARE NOT bolts, but instead, studs retained by nuts. Unless the threads and nuts are gubered with sealant during head installation, a minor leak past the nut is possible. Be sure and tell us how this caper ends. Good Luck.

04-15-2025, 05:23 PM	#8
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 8,043	Re: leaking head bolt I suspect the hole under that stud has been @#$ed up by some ham fisted yobbo sometime. That allows the coolant to get past the thread and up to the top of the head. If you had the head off, I'd recommend a dab of goo on the thread and put it back. With head in place, a little radiator stop leak should do it. I think a blown head gasket is unlikely. __________________ I sometimes wonder what happened to the people who asked me for directions. Even at my age, I still like to look at a young, attractive woman but I can't really remember why.

04-15-2025, 06:51 PM	#9
Big hammer Senior Member Join Date: Jun 2014 Location: Land of Lincoln Posts: 3,430	Re: leaking head bolt That stud is below the nut, could have been pushed through the block, now coolant traveling up past the nut. X-3 on trying cooling system stop leak __________________ Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done

04-15-2025, 01:54 PM	#3
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,856	Re: leaking head bolt Are you getting steam out the exhaust pipe? Is there water in the oil so that it looks like a chocolate milkshake? Are you loosing compression in one or more cylinders? Has the carbon been blown out of one or more cylinders? Are you finding oil in the radiator or bubbles? Does an exhaust gas analyzer indicate exhaust gas in the radiator? If you answered yes to any of these questions then you need a new head gasket. If not then you could probably get by with some gasket sealer under the nut. (I recently discovered Right Stuff gasket sealer that seems to do a good job, but the surfaces have to be cleaned of oil or other contaminates using acetone.) Before you pull the head, you may want to re torque the head to 55 foot-pounds and see if that solves the leak. Do that on a cold engine. The water in the coolant mixture will clean the carbon out of any cylinder where it is present. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 04-15-2025 at 02:41 PM.

04-16-2025, 12:44 AM	#10
ThirstyThirty Senior Member Join Date: Nov 2024 Location: College Station,Texas Posts: 343	Re: leaking head bolt I was recently introduced to this product by a friend with a lot of dealership level repair service experience. I had not heard of it, but he swears by it. He had just picked up an underbelly Kubota mower, diesel, small.... 3 cyl... and it got hot in about 20 mins running. put this in radiator, warmed up engine for a bit... and went to work. Now stays cool. "Radiator?", I asked... "No, pretty sure head gasket....", he said. __________________ "My Model A... work never ends, only the day ends!" Last edited by ThirstyThirty; 04-16-2025 at 12:54 AM. Reason: .

04-16-2025, 09:56 AM	#12
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 5,712	Re: leaking head bolt Have you tried re-torquing the head nuts? From the look of the paint on the head it suggests some recent work on the engine. __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn!

04-16-2025, 01:34 PM	#14
David in San Antonio Senior Member Join Date: Sep 2022 Location: San Antonio Texas Posts: 545	Re: leaking head bolt “….slapped some shmuck on it and reinstalled.” I’m guessing shmuck is a generic term for sealant? __________________ David in San Antonio Late ‘30 Deluxe "Wretched Roadster" Alamo A’s Club

04-17-2025, 05:17 AM	#15
Piet Member Join Date: Apr 2019 Posts: 48	Re: leaking head bolt thanks everyone!! I'm going to try sealant first, if this doesn't work, I can always change the gasket. Toppic can be closed.

04-17-2025, 06:07 AM	#16
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,856	Re: leaking head bolt Piet, Do not change the gasket unless it is leaking. Re torque the nuts to 55 foot-pounds. The leak at the stud is not a head gasket leak. See post #3. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

04-18-2025, 12:06 PM	#18
Phil Brown Senior Member Join Date: May 2010 Location: Santee Calif. Posts: 638	Re: leaking head bolt I would retorque the head first Try your favorite brand of stop leak if retourque did not stop it If still leaking try to get the stud out to add some sealant to the bottom threads of the stud If the stud is stuck,..... you got a head start on pulling the head off Most times stop leak will fix it