Cylinder Head Bolt Leaking Radiator Fluid

kc94507 · Jul 12, 2016

Help!! I have the middle bolt in the Cylinder Head of my 8N engine leaking radiator fluid.

Recently I had tried to remove a bracket on the carbureator linkage that was held on by a Cylinder Head Bolt. When I removed the head bolt it was worn at the threads and almost looked cross threaded. I proceeded to use a thread cleaner to clean up the threads in the Cylinder head. I then attached the bracket with the head bolt and tightened it down. I was pleased because I was able to tighten the bolt and figured the dressing of the threads did its job.

Today I poured in antifreeze in the new radiator and then found out quickly that I had green antifreeze coming out of the head bolt hole (it is the black headed bolt in the picture).

Any suggestions on if this is fixable without removing the head of the engine??

R Geiger · Jul 12, 2016

use some high temp thread sealer on it.

kc94507 · Jul 12, 2016

Oops forgot to upload the picture. Help KC94507

kc94507 · Jul 12, 2016

Are there any worries that fluid is leaking into other areas of the head/pistons/oil pan?

Thanks

HFJ · Jul 12, 2016

i'm confused (not for the first time

) - are 8N heads threaded?

JMOR · Jul 12, 2016

(quoted from post at 17:47:08 07/12/16) Help!! I have the middle bolt in the Cylinder Head of my 8N engine leaking radiator fluid.

Recently I had tried to remove a bracket on the carbureator linkage that was held on by a Cylinder Head Bolt. When I removed the head bolt it was worn at the threads and almost looked cross threaded. I proceeded to use a thread cleaner to clean up the threads in the Cylinder head. I then attached the bracket with the head bolt and tightened it down. I was pleased because I was able to tighten the bolt and figured the dressing of the threads did its job.

Today I poured in antifreeze in the new radiator and then found out quickly that I had green antifreeze coming out of the head bolt hole (it is the black headed bolt in the picture).

Any suggestions on if this is fixable without removing the head of the engine??

ou have to use thread sealer on the bolt, as they screw into the block water jacket.

R Geiger · Jul 12, 2016

(quoted from post at 16:06:33 07/12/16)
i'm confused (not for the first time ) - are 8N heads threaded?

The treads are in the block, not the head.

kc94507 · Jul 12, 2016

(quoted from post at 15:37:57 07/12/16)

(quoted from post at 16:06:33 07/12/16)
i'm confused (not for the first time ) - are 8N heads threaded?

Click to expand...

The treads are in the b etc lock, not the head.

Correct.... Threads in block (my miscommunication) . Can there be other leaking issues?

Bruce (VA) · Jul 12, 2016

No
75 Tips

kc94507 · Jul 12, 2016

I put the bolt back in with Aviation Form A Gasket #3 which is good for temperatures up to 400 F.I gooped the fluid all around the lower threads of the bolt and sort of dripped a bunch in the hole just before inserting the bolt. I notice that the bolt sort of drops in the hole and then starts threading when it bottoms out. Is there any type of gasket material that I need under the head of the bolt where it touches the head? In other words is there cooling water in between where the bolt starts threading (last one inch of a 3" bolt)and the head of the bolt that would run out just under the head of the bolt because the top of the head of the bolt has no gasket or O-Ring?Sorry for my lack of experience. Its been 30 years since I've done a valve job and cant remember how the internal cooling might be routed.

HFJ · Jul 12, 2016

the coolant is only below the threaded end of the bolt. there is no need to seal the head of the bolt.

Cylinder Head Bolt Leaking Radiator Fluid

kc94507

Member

R Geiger

Well-known Member

kc94507

Member

kc94507

Member

HFJ

Well-known Member

JMOR

Well-known Member

R Geiger

Well-known Member

kc94507

Member

Bruce (VA)

Well-known Member

kc94507

Member

HFJ

Well-known Member

Similar threads