Anyone know what causes this ???

#2
Leaking head gasket. The gasket could be bad/damaged and/or the head is warped. Take the head off and clean off the contact surfaces on both the block and the head real good (all traces of the old gasket must be removed). Then true (flatten) the head contact surface using a sheet of 400 grit wet-or-dry sandpaper taped to a perfectly flat surface like a sheet of glass. When you start sanding you will see real quick where the high spots are as they will be shiny while the low surfaces will still be dull. Keep sanding until you get a uniform shiny surface where the gasket makes contact.
Finally, install a new head gasket (I prefer the "old style" metal/asbestos ones over the "newer style" fiber/graphite ones). Make sure and tighten down the head bolts properly using a torque wrench.
Michael
 
Last edited:

BD1

New Member
#3
Leaking head gasket. The gasket could be bad/damaged and/or the head is warped. Take the head off and clean off the contact surfaces on both the block and the head real good (all traces of the old gasket must be removed). Then true (flatten) the head contact surface using a sheet of 400 grit wet-or-dry sandpaper taped to a perfectly flat surface like a sheet of glass. When you start sanding you will see real quick where the high spots are as they will be shiny while the low surfaces will still be dull. Keep sanding until you get a uniform shiny surface where the gasket makes contact.
Finally, install a new head gasket (I prefer the "old style" metal/asbestos ones over the "newer style" fiber/graphite ones). Make sure and tighten down the head bolts properly using a torque wrench.
Michael
Thanks for the response Michael I really appreciate it.
 
#5
Leaking head gasket. The gasket could be bad/damaged and/or the head is warped. Take the head off and clean off the contact surfaces on both the block and the head real good (all traces of the old gasket must be removed). Then true (flatten) the head contact surface using a sheet of 400 grit wet-or-dry sandpaper taped to a perfectly flat surface like a sheet of glass. When you start sanding you will see real quick where the high spots are as they will be shiny while the low surfaces will still be dull. Keep sanding until you get a uniform shiny surface where the gasket makes contact.
Finally, install a new head gasket (I prefer the "old style" metal/asbestos ones over the "newer style" fiber/graphite ones). Make sure and tighten down the head bolts properly using a torque wrench.
Michael
Michael, In addition…
We chase the block threads and the bolt threads as indicated. Clean and air-chuck really well. Then, one drop of light oil in the bolt threads, and assemble.
We were told back in the day that adding this portion to the re-build would assure the bolt was torquing accurately and not just fighting any debris or poor mating surfaces of either thread form.
Is this still a recommended practice?
Steve
 
#6
Michael, In addition…
We chase the block threads and the bolt threads as indicated. Clean and air-chuck really well. Then, one drop of light oil in the bolt threads, and assemble.
We were told back in the day that adding this portion to the re-build would assure the bolt was torquing accurately and not just fighting any debris or poor mating surfaces of either thread form.
Is this still a recommended practice?
Steve
I clean the threads on both the head bolts and block holes real good before reassembly, however, I do not use any oil on the threads.
Michael
 
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