Cat 3412 1997 problems

Sounds like you have water in there. Pretty much the only thing that can explain the high oil level besides diesel but you d have smelled the diesel in the oil

Batteries?

If you find it safe to turn over...

Check battery voltage? If you have a parallel switch, check with that too? Load test battery?

-Chris

First thing I would do is drain the oil to see what you have. That will tell you if you have too much and what you have in there.

Sure it could be the starter wiring or the batteries but that doesn’t explain the high level on the dipstick

Start with the simple stuff: what’s the voltage on your port starting batteries? What does your battery charger show? Did you try your emergency parallel crossover to give the batteries a boost from the stbd side? What does the oil on the dipstick look like? Is it milky? Is it black? Any smell of diesel? When you say the reading on the dip stick is high, how long did you let motor sit after trying to start it before checking oil level? Assume you wiped off dipstick then checked oil again? Sorry, not trying to insult you with simple questions and issues but you didn’t mention any of these so just verifying before everyone jumps to big problems.

When evaluating mechanical issues I always try to keep Known Fiasco Potential (KFp) in mind. In this instance, the KFp couldn’t be much higher. Do the most conservative thing by draining and evaluating the oil before taking any other steps. If the oil change decision is wrong, your only down side is completing an oil change with cold oil…. Seems like a no-brainer

Do you have any evidence of a raw water leak near the water pump or elsewhere in the area? Isn’t the raw water pump gear driven on the 3412?

water being sprayed around still doesn’t explain rust inside the valve cover on one bank or the higher oil level. Speaking of which, is it still high? Are you sure the oil is pure and not emulsified / milky?

you should sent an oil sample for analysis before doing anything

next step would be to pull the injector and scope the combustion chambers.

is the dip stick tube rusty inside?
did you notice crank case pressure while cranking?
have you had the after coolers off in the last 2 years? (pressure testing can weaken them)

Yes, any leak would come out of the weep hole but it is unlikely to be sprayed by the belt as if it was a belt driven pump