Volvo B20 AQ130 Water in Oil

[Hofty]

Hey folks,

So I purchased a boat with a Volvo AQ130 engine. There was emulsified water in the oil. The prior owner claims engine was running fine and had it on the lake and he did not winterize the motor.

Upon breakdown I noticed some corrosion in cylinder 4 and emulsified water/oil in the intake port. Upon further review it appears the water got in via the exhaust manifold as the water jacket had a rusted hole and I can imagine the water entered cylinder 4 and shut down the engine. Does this seem probable?

Take a look at the pictures. Head gasket not blown.

- I will be pulling the pan off to clean all the components. Check cam for wear.
- Removing the oil cooler and checking for any holes in water lines

 

[Lou C]

that water was in there a LONG time, the cyls are very pitted from the pix, not sure if you can save that one.
I had salt water in 2 cyls for about a week, drained the water out and changed the oil like 3x, to save it.
it looked like this when I took the heads off to fix the blown head gaskets, I had pickled it in the fall with fogging oil and cranked it over, didn't get to pull the heads off until the middle of the winter, no rust in the cyls.

 

[kenny nunez]

Another source of water in the oil is the sea water pump. There is a weep hole that if it is plugged then the water ends up in the pan. So take a close look at the pump.

 

[Donald0039]

Most (pleasure) marine engines die of water ingestion rather than wear out. That's why it's important to pull the exhaust manifolds and risers every so many years. Less often fresh water, more often salt water. And in FWC then only the riser needs to be pulled.

So the simplest thing to do is to put it back together with new manifolds and risers, check compression and see how it runs. Check compression again. Low compression can come from rings or rusted valve seat.

Possible work would be honing the cylinder and new rings. Boring the cylinder and new piston & rings. Machining the mating gsurface of the block & head. Valve job on head if the area around the valve seat is rusted.

New short or long block.

Depends on your skills you have, time you have and $$.

 

[Hofty]

So is this a cracked engine block or is it the casting of the block? It looks too uniform to be a cracked block. Thoughts?

I'm having the machine shop check it over in a few weeks regardless, but someone surely has seen this before so figured best to get some input. The Crack (casting?) Goes across entire block appears to be the side of the block which is where casting die is during manufacturing.(casting marks)

 

[Scott Danforth]

that is a casting parting line

 

[Donald0039]

So what are you going to have the machine shop do assume they find to cracks?

Magnaflux of the block & head will find cracks you cannot see with your eye.

 

[Lou C]

agreed that is 100% the best way to go.