Pulling head; what to look for?

[MariaAZ]

I'm going to be pulling the head on the '73 240Z this weekend to see where the water leak is.

The big question; what am I going to be looking for? How will I know if it's a leaking gasket or a problem with the head or... heaven forbid... something with the block itself?

[panchovisa]

If it was actually a problem with the haed gasket it will be quite apparent. Next to one (or multiple) water passages you wil see that the gasket is not tightly compressed/ erroded/ flakey.

If the gasket has broken towards the combustion chamber you should have seen white exhaust at start up and will probably have some errosion of the aluminum head caused by combustion heat/ gasses mixing with H2O/ anti-freeze to create an acid that eats aluminum. Talk to a local engine rebuilder to determine if head needs skim cut/ weld/ or "plastic" metal repair.

A leak between water and oil passages will result in "milky coolant" and contaminated oil (possibly excess "oil" level). Should be no problem with head if it didn't overheat.

A leak between water passge and edge of gasket only results in low water level and mess on outside of engine.

Aleak between oil passage and combustion chamber should have given a blue exhaust at all times. Only concern would be that leak was large enough to starve top end of cylinderhead (cam/ rockers) of lubrication. If that was the case you would hear more "clatter" noise from engine especially at idle (when oil pressure is lowest).

Note that it is possible to have combinations of the four main types of leaks.