Suzuki DF140 Leaking oil into exhaust water

[dpekin]

Hello,

I have a 2006 Suzuki DF140 that has run perfectly. It is always flushed when returning from a trip. Oil changed regularly, etc. It has approximately 500 hours on it.

It recently began leaking unburnt engine oil into the exhaust water stream. I can see a oil sheen on the water when the engine is running. It will loose a lot of oil, on the order of a quart or 2 an hour. There is no water in the oil sump. I believe the crankcase pressure is pushing the oil out an not allowing water in.

It is not burning the oil as there is no smoke. The engine still runs great. It idles smoothly and runs strong so it is not a valve/piston issue.

My suspicion is possible corrosion of the head gasket between an oil gallery and the exhaust cooling water or possible oil sump gasket. The worse case scenario is a corrosion/crack somewhere between the cooling water and oil.

There is another post in this forum with the same symptoms. Unfortunately, the problem and solution was never stated...
http://forums.iboats.com/showthread.php?t=363621

Has anyone seen this before and determined what the failure is?

To diagnose the problem I need to have a flow diagram of the cooling water. Is there anywhere I can get access to the cooling water in the head/right after the head? If I can dump water after the head, I can see if the oil leak is in the head or after. I have read about zincs in the block. If it has them, I could remove one and get an exhaust water stream there, I suppose.

Thanks.

- Dave

 

[Fragamag]

Re: Suzuki DF140 Leaking oil into exhaust water

Man, It sure sounds strange to get that much oil in the exhaust. I may be off base here but if you have a manual, it may show if there is a freeze plug or not. I have no idea that it would, or if it would be located around the base. Even so, you would think it would blow to atmosphere rather than to exhaust.

Your assessment sounds logical, although you would have to overcome the exhaust pressure to push oil in.
It is still possible you lost some oil seals on the exhaust valve stems, and oil is being pushed out the exhaust through the bad oil seals.

If you have an access point exit your exhaust at the block near the valve cam, you might be able to check that port for oil.
Keep us posted.

 

[dpekin]

Re: Suzuki DF140 Leaking oil into exhaust water

Prior to taking the engine into the mechanic, I wanted to try to determine where in the cooling water cycle the oil was being leaked into the cooling water steam. This is easier said than done. I ended up removing the lower zinc from the engine head, inserted a tube in its place to catch the cooling water, and started the engine. The lower zinc is about the same level as the 2nd piston in the head. I filled a bucket with the cooling water from that location and the water was clean. This tells me that the oil leak is between the 2nd cylinder and the exhaust. It still could be a head gasket on the lower cylinders, oil pan gasket or corrosion somewhere in the oil galleries.

The plan now is to take the engine into the mechanic and do a compression and leak-down test to check there isn't anything significantly wrong w/ the power unit. There shouldn't be since the engine runs great, was thoroughly flushed every time it was used, and did not live in the water. It was always dry on a trailer. There are only 528 hours on it. Also when I looked into the water passage when the zinc was removed, it was very clean...

If there is a problem w/ the compression/leak-down test, I won't spend significant $$ on this engine. I'll re-power w/ a Yamaha 150.

If the compression test comes up good, we'll pull the power head and see if we can detect oil in the water passages from the head. If so, it's probably the head gasket. If not, then it's farther down in the engine, probably a oil sump gasket or something.

Also, prior to pulling the engine apart, I'd like to pressurize (10-20 psi) the oil sump/crank case to force more oil to leak. I think we can do that by making an air fitting to go over the dipstick tube. I hope this will force more oil into the now dry water passages. This should make detecting the leak easier.

Stay tuned....

 

[Fragamag]

Re: Suzuki DF140 Leaking oil into exhaust water

I'll be listening.

 

[nelbur]

Re: Suzuki DF140 Leaking oil into exhaust water

The oil is water cooled just behind the oil filter. I have heard of oil being forced by an o-ring and into the cooling water, which of course dumps into the exhaust. I would think you would see any cylinder problems on the spark plugs. I would guess an oil cooler problem would be easier to fix and probably should be ruled out first.

 

[stylesabu]

Re: Suzuki DF140 Leaking oil into exhaust water

i like your idea about pressurizing crankcase

 

[dpekin]

Re: Suzuki DF140 Leaking oil into exhaust water

It turns out that the oil leak was not due to catastrophic head gasket failure or major seals. Whew!

The oil cooling unit had developed a leak. It is under pressure which is why the oil leaked out and the cooling water did not leak into the engine.

All in all, that is about the best outcome I could think of.

- Dave

 

[Fragamag]

Re: Suzuki DF140 Leaking oil into exhaust water

Glad it wasn't any worse.