Yanmar diesel - stops running/all oil leaked out...

[TampaBaySailor]

Hi,

I have a 20 year old Yanmar diesel 3GM30F with unknown number of hours. A few days ago while underway at ~2000 rpm, the engine died without warning after running for 3 hours. A quick inspection showed all engine oil had leaked out.

After a tow back home, I inspected the engine and could not find any obvious place the oil leaked out however the dipstick clearly showed no remaining oil.

Does the CF community have any suggestions what I should do next? Obviously I need to figure out what happened (why the oil leaked) and additionally how badly damaged my engine is from running without oil.

Thanks!

[robert sailor]

And your bilge doest have any oil in it?

[sailorchic34]

A prime suspect is the external oil line between where the banjo bolt where it exists the block to the starter along the side. The mild steel line has a history of rusting out about 3 inches from the bolt connection. I replaced mine with copper, drilling out the original banjo bolts.

The problem is only near the starter not along the opposite side by the lift pump. Yanmar has a replacement one, also of copper for $56 ish.

If DIY, only solder with 425 degree solder nothing higher. Brazing copper will anneal it and it will fail very quickly.

[sailorchic34]

Originally Posted by robert sailor

And your bilge doest have any oil in it?

Ah good point. If no oil in the bilge, then head gasket is the next suspect.

[sailorchic34]

Originally Posted by TampaBaySailor

Hi,

Does the CF community have any suggestions what I should do next? Obviously I need to figure out what happened (why the oil leaked) and additionally how badly damaged my engine is from running without oil.

Thanks!

Is the engine seized or will it still turn. If it's seized, then at the least it needs new bearings and crank turned down and same for connecting rods Possible damage to tappets and cam.

If it turns over, then fix the leak, put oil in it and see how it does. I assume the low oil pressure alarm did not go off.

[Sailorman Ed]

Sailorchic - does the 2 cyl also have the same oil line with the same problem?
If so, this would explain why I keep getting oil in the bilge.
This runs from near the starter to near the lift pump?
thanks,
Ed

[sailorchic34]

Originally Posted by Sailorman Ed

Sailorchic - does the 2 cyl also have the same oil line with the same problem?
If so, this would explain why I keep getting oil in the bilge.
This runs from near the starter to near the lift pump?
thanks,
Ed

All the GM series have that problem, er feature. It's always the line that runs behind the starter that leaks, but the leak forms between the first banjo boslt and starter. You will see the line sort of dimpled from the rust. Pretty much all the 20+ year old gm's could stand to have that line replaced.

$1.50 of 1/8"' copper and a bit of acid core solder from the hardware store does it proud. I changed the routing on mine so the line rises over the starter. That way you don't have to remove the starter. BIG PLUS!. By the way, watch the crush washers that love to fall into the bilge when removing and even more so when reinstalling. That will get you cuss'n like a sailor for sure.

The line runs from about 4" in front of the starter, to behind the starter to a banjo bolt on the back of the head to serve the rockers and then continues around to over the fuel filter to service the cam bearings. Only the section between block/starter and head is the problem.

[daletournier]

Hi , Sailorchic thanks for pointing out the weakness in the external oil pressure line. Later this year I'm most likely going to head back through some remote places, any other suggestions in regards to 3gm30f weaknesses and spare parts? Sorry a little of topic.
Dale.

Sent from my GT-N7105T using Cruisers Sailing Forum mobile app

[FlyingCloud1937]

Yep,

If the oil cooler is on the suction side of the sea water pump, as it should be.

Then that suction, will evacuate the oil, as by design, out the exhaust.

If the cooler is on the pressure side of the sea water pump(a bad design), then the sea water pump will flood your engines(s), and probably your tran(s), did I say bad design.

You should have a failing oil/trans.. pressure SW that alerts the bridge/helm.

If not then it's a bad design to begin with or, an electrical problem.

Lloyd

Originally Posted by TampaBaySailor

Hi,

I have a 20 year old Yanmar diesel 3GM30F with unknown number of hours. A few days ago while underway at ~2000 rpm, the engine died without warning after running for 3 hours. A quick inspection showed all engine oil had leaked out.

After a tow back home, I inspected the engine and could not find any obvious place the oil leaked out however the dipstick clearly showed no remaining oil.

Does the CF community have any suggestions what I should do next? Obviously I need to figure out what happened (why the oil leaked) and additionally how badly damaged my engine is from running without oil.

Thanks!

[twinboat]

The sea water pump is not going to flood your engine. The sea water is about 5 lbs pressure, compaired to 40+ lbs oil pressure.

Any engine I have seen, has the sea water pump before the engine and coolers.



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[TampaBaySailor]

Great ideas - thanks.

There would definitely be oil in my bilge if there wasn't a pan underneath the engine to catch it all before it ended up in the bilge.

I will check the external oil line - sound like that could be it.

Sailorchic34 - how would I check if my engine is frozen? Right now there is no oil in it...

[svfraidknot]

to see if it will turn over put a socket with a break over handle on the nut front end of motor turn with break over handle ,, a friend of mine had work done on his yanmar the mechanic left the bolt out that held the tube that runs down the side of the motor where the check oil dip stick goes ,, after hours of vibration the bottom of the tube broke off and he lost his oil from his motor into the bilges ,, one simple boat one panamanian mechanic cost him a motor ,,

[sailorchic34]

Originally Posted by FlyingCloud1937

Yep,

If the oil cooler is on the suction side of the sea water pump, as it should be.

Then that suction, will evacuate the oil, as by design, out the exhaust.

If the cooler is on the pressure side of the sea water pump(a bad design), then the sea water pump will flood your engines(s), and probably your tran(s), did I say bad design.

You should have a failing oil/trans.. pressure SW that alerts the bridge/helm.

If not then it's a bad design to begin with or, an electrical problem.

Lloyd

Just a note that the GM series engines doesn't have an oil cooler.

Agree that the Oil pressure switch needs to be looked at too. or the wiring

[sailorchic34]

Originally Posted by TampaBaySailor

Sailorchic34 - how would I check if my engine is frozen? Right now there is no oil in it...

As SVFraidKnot said, put a wrench on the crank pully bolt and see if it turns over. Pull the decompression levers first, just so there is no chance it would start.

If it turns easily, your lucky and you just need a $58 oil line. If it does not turn, Well lets not talk about that. Though if the oil leaked out and the oil pressure alarm did not go off, then odds are it might be a tad stuck.

Depending how handy you are with a wrench would effect the cost of a rebuild. Figure $700 ish for machining and about $1000 for parts. (Bearings are cheap), if you can turn a wrench. If you have to pay someone else to do it, it would cost as much as a new engine.

Beta BTW is the engine to get as they can match up the engine mounts, which makes a repower soooo much easier.

[sailorchic34]

Originally Posted by daletournier

Hi , Sailorchic thanks for pointing out the weakness in the external oil pressure line. Later this year I'm most likely going to head back through some remote places, any other suggestions in regards to 3gm30f weaknesses and spare parts? Sorry a little of topic.
Dale.

Sent from my GT-N7105T using Cruisers Sailing Forum mobile app

Actually other then the external oil line and a slight problem with piston lands breaking on 92-94 GM's, they are tough little engines. I had 1000 hours on mine, when the lands broke on #3 pistion (1994 engine). Everything else measured out well within New engine tolerances. I put $700 in parts and $300 to #3 bored and sleeved and 1 and 2 lightly honed. Today, 1-1/2 years later, I have 250 hours on it and its still going strong.

To the OP, to pull the crank in a GM engine, you need a special tool, a 36mm 6" deep socket. I had Bubba (I named mine) made for less then $100. Yanmar has it for $190.