M38 jeep head studs leaking

jimbob · Post by **jimbob** » Mon Mar 14, 2011 7:07 am

I have a m38 new rebuilt engine. Head bolt studs are leaking water, I have sealed the studs with permatex thread sealer but some of the studs are still leaking. Does anyone have a recommendation on how to stop the leaking studs?

Jim

Post by **wesk** » Mon Mar 14, 2011 9:07 am

The correct Permatex product to use is Permatex #1 Form-a-gasket.

Seriously worn threads in the block or the studs can make sealing difficult. Did the studs wobble during installation?

As a last resort a very small cross section "O" ring that fits the stud snugly then install the head.

jimbob · Post by **jimbob** » Mon Mar 14, 2011 1:38 pm

Thanks for info. Wes

Jim

Post by **wesk** » Tue Mar 15, 2011 9:56 am

Hello Jim,

A couple of more points.

The thread sealer versions from the chemical companies generally only work in tight fits. The Permatex #1 gasket maker is what I use. If there are any crackes around the threaded holes you may still get fluid leaks. Also a fluid leak past the head gasket can find it's way up beside a stud/bolt shank and make the stud/bolt look like the source of the leak. So the first step is to run the newly assembled engine until it is up to normal
operating temp. Then re-torque the head bolts/stud nuts. If the leak stops
you win. If not mark or map the leaks before you pull the head on a piece
of paper and then drain the coolant before you remove the head. Then
carefully lift the head so as not to disturb any deposits or marks on the
surfaces. If any of the studs are loose enough to rock in their holes you
will continue to have problems. If worn threads are the issue and you are
not extremely intimate with how to work with threaded inserts then take
the engine to a machine shop and have them install the new threaded
inserts.

Wes K