Sudden oil loss-Yanmar

[westwinds]

Originally Posted by wingssail

No smoke out the oil fill cap, no smoke or oil collecting out the breather hose (goes to air cleaner)...

That eliminates bad rings or cylinder wear from bad injector. Bad injector would also result in black smoke after warmup. My guess would be bad mechanical fuel pump if the engine has one. A new mechanical pump or an electric fuel pump to take its place I think would be worth the money as a trouble shooting technique. I suppose a compression check could be done to make sure engine oil is not getting by the piston rings. I think some tests should be done to eliminate some of the theories on what the problem could be.

[Terra Nova]

34--I've already made it clear what I think happened.

[sailorchic34]

Originally Posted by Terra Nova

34--I've already made it clear what I think happened.

Sorry I thought you were joking. So the other 6 quarts the OP put in the engine went where.


In the case of the 3jh2e, the lift pump, is located on the lower side of the injector pump housing and the lift pump plunger is driven by the injector pump cam. There is a external oil line connected from the block to the separate injector pump housing to lube the cam and bearing. Looks like the oil drains out through the bearing and and may have a wet sump at the fuel pump plunger height, based on parts diagrams and photo's.

If the injector pump housing has a small wet sump as it appears it would have, then it would be very possible for the fuel lift pump to suck oil in via a tear in the diaphragm. But only if the fuel filter was mostly clogged, as it seemed to have been.

Simple and logical.

[westwinds]

Originally Posted by sailorchic34

Sorry I thought you were joking. So the other 6 quarts the OP put in the engine went where.


In the case of the 3jh2e, the lift pump, is located on the lower side of the injector pump housing and the lift pump plunger is driven by the injector pump cam. There is a external oil line connected from the block to the separate injector pump housing to lube the cam and bearing. Looks like the oil drains out through the bearing and and may have a wet sump at the fuel pump plunger height, based on parts diagrams and photo's.

If the injector pump housing has a small wet sump as it appears it would have, then it would be very possible for the fuel lift pump to suck oil in via a tear in the diaphragm. But only if the fuel filter was mostly clogged, as it seemed to have been.

Simple and logical.

Yup, have to agree. Is the lift pump replaceable without having to replace the fuel injection pump?

[wingssail]

Well, we've exhausted everyone's ideas about what could be wrong with Wing's motor, tested the oil cooler and fuel pump diaphragm and a lot more and we've found nothing.
Further, the problem is no longer evident; we're not losing any oil now, and we've put about five hours of operation on it without any loss.
So we are left with three choices:
1. We had a serious problem which we still have since nothing was fixed, but it's in remission.
2. We had a serious problem which fixed itself.
3. We never had a problem, we just thought we did.
Frankly I am leaning toward door number three, which is the same view as my mechanic here in Puntarenas, William, who seems to be very competent and thorough, and is highly recommended by several sources. William doesn't know what to think, he can't find anything wrong and can't say anything but good stuff about what he sees in our motor, although he's puzzled by the oil loss I reported. He also brought two other mechanics by to consult on the problem.
Possibly he doubts my report about the oil loss in the first place but it's hard to argue with the empty oil containers which we kept and anyhow, he's too polite to say so.
So, after a rigorous run up today, and no evidence of any problem, and having checked everything short of doing a major tear down, we'll cross our fingers, carry a lot of spare oil, and move on.

Thank you all for your interest.

[westwinds]

Well, replacing the plugged fuel filter would reduce the "sucking" of oil across the pump diaphram and that could explain the sudden reduction in oil loss. You could put the old fuel filter back on and see the problem occurs again. However, consider that a lift pump with hole in it could dump diesel into the crankcase if there is enough change in fuel pump pressure on the diaphram. With enough diesel and a hot engine, the bearings could be destroyed from too thin a lubrication oil. I would replace the lift pump. If you put your thump on the suction side of the pump inlet and operate the lever, the suction should hold until you take you thumb off the inlet. If the suction is gone in a few seconds, well there is a hole in the diaphram.

That oil had to go someplace. Also, diesels do not tolerate lost of lubrication like a gasoline engine and a modern gasoline at freeway speeds can suffer bearing damage in three minutes without any oil. So, watch your oil level.

[Cheechako]

Originally Posted by wingssail

Well, we've exhausted everyone's ideas about what could be wrong with Wing's motor, tested the oil cooler and fuel pump diaphragm and a lot more and we've found nothing.
Further, the problem is no longer evident; we're not losing any oil now, and we've put about five hours of operation on it without any loss.
So we are left with three choices:
1. We had a serious problem which we still have since nothing was fixed, but it's in remission.
2. We had a serious problem which fixed itself.
3. We never had a problem, we just thought we did.
Frankly I am leaning toward door number three, which is the same view as my mechanic here in Puntarenas, William, who seems to be very competent and thorough, and is highly recommended by several sources. William doesn't know what to think, he can't find anything wrong and can't say anything but good stuff about what he sees in our motor, although he's puzzled by the oil loss I reported. He also brought two other mechanics by to consult on the problem.
Possibly he doubts my report about the oil loss in the first place but it's hard to argue with the empty oil containers which we kept and anyhow, he's too polite to say so.
So, after a rigorous run up today, and no evidence of any problem, and having checked everything short of doing a major tear down, we'll cross our fingers, carry a lot of spare oil, and move on.

Thank you all for your interest.

I've been leaning toward #3 for some time now! It aint witchcraft! The oil had to go somewhere or the measurement data is wrong. The oil either returned to the fuel tank somehow, or option #3.

[marlinmike]

I don't think you can wish away 8qts of oil, sailorchic34 had what I believe is the best explaination for the disapearance then anyone, when that filter starts clogging again it will re-appear.