DD 6V92 Overhaul??

[Reelsly]

Here's the quick history. I own a '98 550DB with DD 6V92 625hp motors with 1750hrs. I've owned the boat for less than a year and I don't have much of a history. The survey (from a reliable Detroit guy) came back great. Last week, I was running for about 2.5hours at 1750rpms at 170 temp. Up and down through some no wake zones. All of a sudden the port motor temp spikes to over 190 and a low coolant alarm sounds. I immediately slow and turn the motor off. Too hot to check coolant. Strainer is empty and nothing is blocking the water intake. Get to the dock. No coolant existing. Added 12 gallons. Checked oil before restarting and see that there is water in the oil. I stop here.

Since I'm out of town, I find a Detroit mechanic (not my guy). He comes down and inspects. Says I need a complete overhaul ($21K) and one head is definitely cracked. All O rings are fried.

Here is my question. In the past year, there hasn't been any overheating problems. Do you think a head can really crack that quickly. I plan to get a second opinion. Is $21K accurate for an overhaul? Using Detroit parts, no aftermarket crap.

I'd like some advice on how to proceed. Questions to ask the mechanic. I want to make an educated decision.

Thanks

 

[barlow]

From memory Steve dancer500 (I think) has had a similar experience with these engines.

 

[bahamabreisus]

I would think it would need to be way more than 190 degrees to crack a head. Oil in water sounds like a head gasket issue ? 2nd opinion is needed.

 

[PMC]

Does that engine have an oil cooler on the coolant side,