Water in the oil

[888]

Working on a 1987 5.7l mercruiser. Discovered water in oil and not sure if its a head gasket,Intake gasket or risers and manifolds.
Supposedly the port side head was removed before purchase and valve job was done. Sure seems to me that port side head gasket is junk..
Heres my compression tests

Cylinder dry wet
1 --- 128 147
2 --- 147 160
3 --- 130 150
4 --- 128 145
5 --- 130 152
6 --- 162 170
7 --- 130 147
8 --- 162 170

 

[Bondo]

Re: Water in the oil

Working on a 1987 5.7l mercruiser. Discovered water in oil and not sure if its a head gasket,Intake gasket or risers and manifolds.
Supposedly the port side head was removed before purchase and valve job was done. Sure seems to me that port side head gasket is junk..
Heres my compression tests

Cylinder dry wet
1 --- 128 147
2 --- 147 160
3 --- 130 150
4 --- 128 145
5 --- 130 152
6 --- 162 170
7 --- 130 147
8 --- 162 170

Ayuh,..... I've seen worse numbers,...

Water in the oil is a cracked block, not a head gasket,...

Any signs of any water on any of the spark plugs,..??

 

[888]

Re: Water in the oil

#7 plug was aweful clean,the rest looked good

 

[Bondo]

Re: Water in the oil

#7 plug was aweful clean,the rest looked good

Ayuh,.... Drain it, 'n air pressure test the block,....

 

[888]

Re: Water in the oil

Got any advice on how I should approach that? Id image just plug inlet and pump air into the outlet?

 

[Bamaman1]

Re: Water in the oil

Easiest thing is to find a really good engine builder/auto mechanic, and have him test the engine.

There's no reason to use a marine mechanic as the good ones this time of the year are backed up a few weeks on repairs--and they're too expensive.

My son in law was a master mechanic, and he built Pro Stock drag cars. Give him such a motor, and he's find the problem within an hour--even if he had to disassemble the top end.

Freezing water is what kills so many inboard outboards--and why marine salvage yards are full of old I/O hulls. I've never seen air freeze--and I always made sure the blocks were drained early in the Fall.

 

[888]

Re: Water in the oil

Easiest thing is to find a really good engine builder/auto mechanic, and have him test the engine.

There's no reason to use a marine mechanic as the good ones this time of the year are backed up a few weeks on repairs--and they're too expensive.

My son in law was a master mechanic, and he built Pro Stock drag cars. Give him such a motor, and he's find the problem within an hour--even if he had to disassemble the top end.

Freezing water is what kills so many inboard outboards--and why marine salvage yards are full of old I/O hulls. I've never seen air freeze--and I always made sure the blocks were drained early in the Fall.

The block was and always is drained....Finding a good engine builder or mechanic doesn't sound like a way for me to learn how to do it next time and save money to boot.

 

[Bt Doctur]

Re: Water in the oil

pull the heads, mark and remove the valves. you checking for a cracked head near the valve seat. cant see the crack with the valve in the head. When removing the heads look closely at the head gasket between the cylinders for black areas. There where compression is crossing between cylinders.
Could use a compression tester hose hooked to a air source and listen

 

[flipbro]

Re: Water in the oil

With those #s i wouldn't think head gasket or head! Pressure test the cooling system (Block) Or pull the intake manifold and look 4 a crack as in my experience that's were ive always Seen them crack other then between the casting plugs AKA FROST PLUGS. Good luck! By the way how much water you talking bout? Now that i think about it i suppose it could be head gasket! When the head was in stalled Did they use a marine head gasket or auto? If auto i guess it could have rusted around a water jacket and is leaking into the lifter valley just a thought.

 

[888]

Re: Water in the oil

When the head was in stalled Did they use a marine head gasket or auto? If auto i guess it could have rusted around a water jacket and is leaking into the lifter valley just a thought.

I dont know what gasket they used but i was thinking the same. Gonna do a leak down on cylinder then pressure test cooling system

 

[airdvr1227]

Re: Water in the oil

The block was and always is drained..

.but earlier you said something about the motor having a valve job, so you don't really know the history. Trust us...you've got a cracked block.

 

[888]

Re: Water in the oil

Turns out i do have a crack all right but not in the block....The head is cracked between #7 valves

 

[flipbro]

Re: Water in the oil

That sucks! But on the up side its a heck of alot cheaper to fix.