leaking head bolt

P

Piet

Member
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?
 

Attachments

  • 20250415_164203.jpg
    20250415_164203.jpg
    35.2 KB · Views: 97
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.
 
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.
 
Last edited:
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 said:
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.
Click to expand...
Probably goes without saying but... if you choose this route, be sure to drain the coolant first.
 
Ruth said:
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.
Click to expand...

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.

1.jpg


9lYlJz7nGhvnnc6LwKb9IR5lmGxvyjEbM0AAAA==


Joe K
 
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.
 
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.
 
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
 
AzBYAxCyeMaFQTxf1pRJ3nnr64VWejibCyPZDVBnviNhpxg6nS.webp

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.
 
Last edited:
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.
 
ThirstyThirty said:
AzBYAxCyeMaFQTxf1pRJ3nnr64VWejibCyPZDVBnviNhpxg6nS.webp

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.
Click to expand...

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

Toppic can be closed.
 
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.
 
Piet said:
thanks everyone!! I'm going to try sealant first, if this doesn't work, I can always change the gasket.
Topic can be closed.
Click to expand...
talked it over with my friend this morning over a cup of
32.png
/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! :)
 
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 :eek:
Most times stop leak will fix it
 
You must log in or register to reply here.
Back
Top