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7.4 L Volvo Penta turned into a milkshake - what to tell the mechanic

V

vetting

New member
Have a buddy with a 7.4 L Volvo Penta (GEN6 GM Marine block. 7.4 liter, 454ci)
that made a major oil/water milkshake on the way back to the slip last week. The breather hoses that route back into the flame arrester puked the milkshake over the top of the block. The water was never just sitting in the motor so it was at least "frothy" oil/water mix. I know that isnt the ideal lubrication situation, but they are trying to tell him that bearings/rings/crank are all going to have a bunch of issues in the future. Personally I think it is salvageable (since it wasnt run that long) if its just a riser, intake gasket, cracked head, or head gasket. I cant imagine that its a cracked block/winterization issue since multiple trips were run on the boat this year.

Any suggestions on how to proceed?
 
Ayuh,..... Pressure test it, find, 'n fix the leak,....
Then get it running, 'n change the oil a couple times,.....

Saltwater, or fresh,..??
 
vetting said:
Any suggestions on how to proceed?
Click to expand...
bondo pretty much covered the DIY route.

But your question was what to tell the mechanic, so it sounds like your buddy might not be capable of this repair. It's a different story if he's paying $150 an hour.
The mechanic is correct that there maybe damage to the internal parts of the motor and this isn't a very new motor. For an engine to puke that much water/oil mix out means that this probably isn't something simple. Also means this wasn't "a little bit" of water. A riser won't do it, could be a intake gasket or cracked head. But what caused the gasket to fail or the head to crack? 7.4s weren't known to have something like that happen without something else causing it. So what the mechanic is worried about is spending the $$$ to find and repair the problem, then your buddy uses the boat a couple of times and a rod bearing spins or a couple of lobes on the cam wear down. And now he's back and still looking at a total rebuild, only now he's out the money for the first repair. Ain't nobody happy at that point!

What to tell the mechanic ---- the truth.

What to ask the mechanic? For estimate on a used/rebuilt replacement engine or if they think they can diagnose why this happened for a few hundred dollars and then the buddy might be able to make a better informed decision.
 
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