318 Water in two cylinders

[Jim Miller]

After an overheat situation, found a crack in exhaust elbow. Further examination showed water mixing with oil after operating briefly (<10 minutes). NO foaming from dipstick tube, just milky oil evident on dipstick. Removed sparkplugs to perform compression check. When cranking for 1st test, water was expelled out of two adjacent cylinders. Water was also evident in exhaust manifold when removed as well. Unsure age of manifolds, except have had boat since 2005 and have not replaced them, yet.
So is this a:
1. cracked block?
2. cracked manifold?
3. blown head gasket?
4 ?

Your thoughts would be appreciated.

 

[tolly_family]

Maniflods and risers first.

Dan

 

[greasemonkey]

pressure test cooling system, listen in the spark plug hole for noise

 

[Jim Miller]

How do you pressure test a raw water system? Listen in spark plug hole for noise? What kinda of noise?

 

[WoodieMan]

Ditto Dan, but after an overheat, anything is possible; head gasket, cracked block etc.

 

[bcclew]

if you dont have a presure testor take off thermostat housing if you have and air compressor even a small one youll need to get and a adaptor put in spark plug hole in one cyl look for air bubbles in thermo housing then do each cyl one at a time if bubbles head has to come off could be gasket cracked head or block if no bubbles at all cyls exhaust manifolds or risers also check intake manifold dont forget if you change exhaust manifolds do risers also hope this helps

 

[tolly_family]

Most auto parts stores will loan you a radiator pressure tester that will work fine on your boat.

Dan

 

[WoodieMan]

Just reread your first post. Do the tests mentioned above but it is not uncommon to get water in the cylinders after overheating. Doesn't necessarily mean something else has cracked but check to make sure.