Farmall 400, coolant coming from head bolt (pic)

SW EM · Oct 29, 2017

Hey guys,

I just finished retorquing my cylinder head after replacing the head gasket. Once I had it up to operating temp for the second time I noticed coolant coming from between a nut and cylinder stud, as if it was traveling through the threads.

What is the correct way to fix this problem? I don't believe their should be any access point for the head stud to get coolant, other than through the head gasket or cracked cylinder head. However I just had the head tested for cracks.

Replace the head stud and nut? Some type of thread sealant?

Thanks in advance

David G · Oct 29, 2017

Is that correct to have bolt there instead of stud, does it screw into water jacket?

rustred · Oct 29, 2017

did u have the studs out of block? and yes they should be sealed. i would use blue locktite only on the studs to block. the nuts need to be lubed with oil , i use copper coat paste on mine.
maybe there is a crack in the block there at the threads??
looks like u have 2 valve cover gaskets on it not positioned too good.

David G · Oct 29, 2017

That is my thought, bolt is leaking through threads.

Is the bolt correct?

Why the double gasket on cover?

David G · Oct 29, 2017

The reason studs are used is because the part that goes into the block is course thread and the part with the nut is fine thread, they will provide more clamping force without stripping. Any stud or bolt that goes into the water jacket needs those threads sealed.

Redturbo · Oct 29, 2017

Less than 3 months ago, I also replaced the headgasket on a 400 Farmall Gas. The studs on the manifold side of the engine go into coolant for sure. I used pipe sealant on all studs that go into the cooling system, did the same with my Dad's H couple years ago. Not trying to nit pick, but the studs really should be a thread or two above the nut.

SW EM · Oct 30, 2017

Thanks everyone for the insight. I didn't
notice the head studs had access to the
water jacket on the manifold side. I'm
suprised only 1 leaks then.

I will apply a sealant to them. Take one
off, seal, retourque...etc.

BarnyardEngineering · Oct 31, 2017

What's with the double valve cover gaskets?

You can "glue" them together with a little permatex gasket sealant so they don't look as sloppy and stand less of a chance leaking, if two are necessary. Not gobs of permatex, just a smear is all it takes.

Farmall 400, coolant coming from head bolt (pic)

SW EM

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rustred

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Redturbo

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