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Where did the oil go?

R

rustyeod

New member
Good Afternoon
I have a 1985 6V71T and this weekend I warmed it up, moved over to the pumpout and shut down, all ran great. restarted after pumpout and alarm would not stop. secured engine and went below to find most of the oil was gone. (it was all there before startup) Filled back up and restarted, but alarm would not stop. shut down and retuned to slip using 2nd engine. I left it for the whole weekend and when I returned to troubleshoot the oil level was good so I started it and it ran and the alarm shut off after the pressure came up (5 seconds). Did not run it long since unsure of the problem.

There wasnt any external oil to be seen,
some sheen coming out of exhaust over the weekend (engine off)
No noticeable oil in heat exchanger

Any suggestions on which way to go? If it was the oil cooler shouldn't there be oil in the heat exchanger? Or is the oil cooler cooled with raw water?
 
A few possibilities come to mind but first, let's clarify how much oil are we talking about here? If you're talking about the oil on the dipstick then it would be about 4 or 5 quarts. "most of the oil was all gone" would be more like 5 gallons.

Typically the heat exchangers for these is a manifold type used to cool the engine block coolant and the oil in a separate chamber. But, any number of configurations are possible so you would need to sort that out or have someone look at it for you as that is indeed a likely place to suspect.

Other things that come to mind are:
Is the transmission overfull? Could be a rear main seal filling the bell housing.
Pop the valve covers and see if one of the heads is not draining. One of those covers could hold a few quarts of oil.
Turbo seal. Pull the exhaust pipe at turbo and see if turbine wheel is oiled or badly coked up.

Good hunting.
 
Last edited:
JGMO
Thanks for the reply. It took 4 quarts to get it back up to the mark on the dip stick. I did have a conversation with my mechanic buddy and when I get a free minute (I have a marine canvas business) I will start all over and check everything again as well as removing the valve covers, checking the transmission and up inbetween the two heads.
 
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