8.1Gi milky oil and making oil

[smcdonn]

Just bought a 2001 Cobalt 246 with the 8.1Gi. Oil was changed just before we bought it according to the previous owner. Oil level was good when we bought it, after running it for a few hours it has made about 2-3 qts of oil and it's very milky. I'm going to change it a couple of times and flush it out and start with a fresh change, but I wanted to discuss where the water could be coming from. First off, boat runs very strong and doesn't smoke or do weird things when the captains call is on, so I feel like head gaskets would give me some smoke and smell if it was a head gasket. Dealer immediately said a cracked block when I called for an opinion, but I've laid in the bay and looked the engine over extensively and can find zero signs of it freezing and cracking. I noticed when I pulled the oil fill cap it was full of water/condensation. I could run my finger around the fill tube and it was wet with clear water. I thought maybe intake manifold gasket but I learned that the 8.1 doesn't pump water thru the intake manifold (someone correct me if this info is wrong). Last thing is the oil cooler, but from the folks I've discussed it with say it's not a common failure.

Any input?

 

[alldodge]

It's not the oil cooler. The oil pressure is higher then the water pressure, and if cooler had a crack the oil would be leaking out and into the water. Oil level would drop

I would think head gasket. Pull the plugs and see which one(s) look steamed cleaned

 

[tpenfield]

Welcome to iBoats . . .

I think I know why the PO changed the oil before selling the boat . . .

If the engine has a full closed cooling system, it would be fairly easy to pressure test the block and find (hear) the leak.

What inspections did you have done before buying the boat? What warranties does the dealer have in the sales contract?

I think based on the amount of water in just a few hours of operation, it is a cracked block or a really bad exhaust manifold.

The 2001 V-P should be a GM big block (496 Cu In) engine.

 

[Scott Danforth]

My guess is it's not the head gaskets

My first thought is a cracked block or leaking exhaust manifold.

Pressure test

 

[Bondo]

Dealer immediately said a cracked block when I called for an opinion, but I've laid in the bay and looked the engine over extensively and can find zero signs of it freezing and cracking.

Ayuh,..... Welcome Aboard,...... Readin' yer story, I'm with the dealer, as it does get cold there,.....

Cast iron blocks can, 'n do easily crack to the inside the oil cavity, 'n not necessarily to the outside of the block,....

To test it, drain all the water outa the block, isolate the block from the rest of the cooling system, 'n pressurize with 'bout 15 psi of air,....
Then listen,.... follow the sound of hissing air to the cracks,....

 

[smcdonn]

Welcome to iBoats . . .

I think I know why the PO changed the oil before selling the boat . . .

If the engine has a full closed cooling system, it would be fairly easy to pressure test the block and find (hear) the leak.

What inspections did you have done before buying the boat? What warranties does the dealer have in the sales contract?

I think based on the amount of water in just a few hours of operation, it is a cracked block or a really bad exhaust manifold.

The 2001 V-P should be a GM big block (496 Cu In) engine.

It was from an individual so no warranty. We took the boat for a test ride before buying and that was it. Only good thing is that even if I have to put a new motor in it, I'll still be in it less than a dealer would have wanted for it.