OH-OH Where did my oil go?

[TROUBLE]

I have a pair of 8V53 Naturals with approx 1375 hours on each. Since owning the boat (about 30 Hours so far) I have checked the oil after each trip. None longer than 3 hrs one way so-far. My port engine seems to burn or leak about a pint of oil every 3 hrs or so and the stbd engine hasent used any oil at all yet. Tonight after a 3 hr boat ride on tuesday, i checked the oil and nothing read on either dip stick. the stbd engine took 3 quarts and the port engine took 5. After filling the engines i ran the boat, brought it up to temprature and went down stairs to look for visual leaks. there were none. There is no extra oil in by bilges and the motors dont smoke. Also i cruise at 1500rpms most of the time and have only spent maybe a total of one hour at 2300. Whats happening?

Art

[REBrueckner]

You have only three choices: you are either burning the oil via combustion, leaking it from the engine into the bilge or leaking the oil into an oil cooler..... from which it goes overboard if raw water cooled.

If your oil coolers are fresh water cooled, check each expansion tank by removing the fill cap and wiping your finger into the coolant and/ or the under side of the expansion tank...if you are losing oil into the coolant you'll be able to feel it and see it a black slick film on your finger. If so, you'll have to flush your coolant system and replace the contaminated coolant.

odd that both engines would use oil irregularly and simultaneously....Did you lose the large amount of oil during the 2300 RPM run period??? Maybe it's possible your rings were sticky and you blew by and burned some oil.....maybe that's cleared up from the high RPM blow out....and the rings are seating properly again????

[Glory]

What grade and brand of oil are you using?

JM

[hibanx]

How soon after running are you checking the oil level? It takes several minutes for all of the oil to drain back into the pan. Check it when its cold to be sure you are not overfiling.

[TROUBLE]

I havent changed the oil in the boat because the po told me he did it a short time before i purchased it. The oil i have been adding when necessary is exxon hd3-40. As far as checking the oil level, i usually do it at least a day after a trip. During the trip that seemed to use all the oil i never went over 1500 rpms. I spoke with the po and he also told me i shouldnt run the boat at 1500rpms. He said i am dogging the engines at that rpm and should run the boat on a plane. Is that true? I dont mind going slow, the motors run cooler and my fuel consumption is a lot less.

Thanks
Art

[piripucha]

Take a look in the transmissions, if they are Allison, the oil may have migrated to them if you have bad seals. This is happening to me with my 8V71TI.

[yachtsmanbill]

Take a look in the transmissions, if they are Allison, the oil may have migrated to them if you have bad seals. This is happening to me with my 8V71TI.

BINGO !!!!

[Tim Powell]

Take a look in the transmissions, if they are Allison, the oil may have migrated to them if you have bad seals. This is happening to me with my 8V71TI.

don"t u gotta remove the gear to replace the seals/o hello!

[yachtsmanbill]

Pull the strainer out.Cut a section out of the salon floor and rig a hoist. Unbolt the gear, flywheel, gasket for trans to block, maybe the trans coupling. Mite as well do the packing gland AND of course, an ALIGNMENT job, not to mention motor mounts.
Ah, the seal!! Use an installer and probably a detroit shaft repair sleeve where the seal rides. Oh... BTW, they also recommend new flywheel bolts every time too...
I gave it about 7 days on mine plus the gear overhaul while its out. No extra charge for the GoJo hand cleaner!! I'm ready for the starboard side this year... ws

[Tim Powell]

Pull the strainer out.Cut a section out of the salon floor and rig a hoist. Unbolt the gear, flywheel, gasket for trans to block, maybe the trans coupling. Mite as well do the packing gland AND of course, an ALIGNMENT job, not to mention motor mounts.
Ah, the seal!! Use an installer and probably a detroit shaft repair sleeve where the seal rides. Oh... BTW, they also recommend new flywheel bolts every time too...
I gave it about 7 days on mine plus the gear overhaul while its out. No extra charge for the GoJo hand cleaner!! I'm ready for the starboard side this year... ws

OH=OH Where did my gold go?