2002 JC tritoon 5.0 MPI mercrusier water in the oil?

[Corbinsc35]

Hello,

I recently purchased a 2002 JC tritoon with a 5.0 MPI Mercruiser engine.

The previous owner said the boat only had 1 hour on the engine since the last time he changed the oil. Well we decided to change the oil in the boat ourselves anyways before we ran it. The oil was very light and milky looking. Too me it looks like water is inside the oil.

I attached a picture of the oil drain pan.

Does anyone know what would cause this and how to fix it?

 

[Scott06]

Thats more than a little water -

cracked block or heads from improper winterization
cracked or rotted out water cross over in intake
rotted out exhaust manifolds, elbows or risers

you may have been sold a boat with a cracked block ... I'd pressure test the cooling system to verify

If it was frozen a new or reman long block is about $2400-4 k

 

[Corbinsc35]

Thats more than a little water -

cracked block or heads from improper winterization
cracked or rotted out water cross over in intake
rotted out exhaust manifolds, elbows or risers

you may have been sold a boat with a cracked block ... I'd pressure test the cooling system to verify

If it was frozen a new or reman long block is about $2400-4 k

I pressure tested the engine the other day when I changed the plugs and plug wires. The pressure was pretty high in each of the holes. The PSI reader was getting 120-180PSI on all 8 of the plugs.

So maybe its the exhaust manifolds, what do you think?

 

[Scott06]

I pressure tested the engine the other day when I changed the plugs and plug wires. The pressure was pretty high in each of the holes. The PSI reader was getting 120-180PSI on all 8 of the plugs.

So maybe its the exhaust manifolds, what do you think?

Not compression test as you outline above . Pressure test the cooling system on the engine.

I'm assuming this is a raw water cooled engine ? Where the cooling water circulates through the engine block, heads, and exhaust manifolds there is raw water that can freeze if the engine isnt properly drained during winterization. This is very common issue due to lack of maintenace/basic care. An engine can have perfect compression and be cracked.

If the water freezes and cracks the block when you run it cooling water will push through the crack into the oil sump creating what you see in your oil.

To do a pressure test you disconnect the supply and discharge hoses, plug them up with pipe plugs, pressure with 15 psi compressed air. If it holds its not cracked. if ot doesnt hold you need to chase down the leak.

Depedning on which of the several cooling setups merc offers people here can walk you through how to do it.

 

[QBhoy]

I think most likely that this is from frost damage. I’m almost sure that it probably isn’t from corrosion on the risers...perhaps because I think most of these mpi engines have the so called safe risers that try to prevent that. May be wrong though.