When DF140 oil cooler leaks

[Grumpy56]

Lost about 4 quarts of oil in a few hours on Sunday in 2005 DF140. Searched the forum, appears first place to look is at the oil cooler. Then the oil cooler does leak, is it obvious? If I remove the oil cooler, should I be able to see where it is leaking?

Craig

[Ole Joe]

Craig,

You ask, "When the oil cooler leaks, is it obvious"? I would say yes, but in my case it amounted to a slight oil sheen in the exhaust water from the strb engine and a trace of water in the oil of the port engine. Neither of my leaks
were significant enough to reach the volume you describe losing.

With regard to visually seeing why it is leaking, yes, if you take the cooler apart while it is on the bench. If you go to the Suzukzi Parts link above and open the oil filter page for your engine you will see a diagram showing the cooler.

The inner (cooler portion) is pressed into the outer housing. Where these units join, they are sealed with O-rings. To separate the two pieces you need to press the cooler out of the housing. If you don't have a press, you can use a vise with a wood pusher on the center of the cooler and shims against the edges of housing base. Slow, even pressure along with some PB Blaster should seperate the two. Look for O-ring failure and/or corrosion adjacent to and under the O-ring.





However, I can't imagine you could lose that much oil that fast through the cooler o-rings. It would require a massive failure of the cooler casting pumping all the oil out the exhaust. Did you notice oil in the water with your exhaust water?

Could the oil filter gasket have worked loose from the cooler and dumped the oil?

And/or, could the cooler be loose at the block allowing the oil to dump outside the block? Part #1 holds the cooler against the block as well as holds the filter against the cooler. Could part #1 have been loosened while trying to remove a stuck filter?

Ole Joe

[redlowrey]

Remove the two water pipes from the cooler and plug them or join them, then run the engine on the muffs bring the revs up so you will increase oil pressure and if the oil cooler is leaking you will see the oil coming out of the cooler pipe.

There should be a sheen in the water from the oil if the cooler is leaking, make sure the engine is hot. You won't have water in the sump if it is leaking it will be going out the exhaust with the water.

[Lunchmoney]

Red is spot on as usual. You should have noticed a sheen on the surface behind the boat for sure, losing that much oil. You can pick up a barbed brass or plastic nipple at your local hardware store to join the tubes or just twist a small screw into the ends of them to plug them.

[Moonlighter]

Losing that much oil so quickly - the first place I would have looked is the oil filter.

A split oil filter or a filter that has a blown or leaking seal. Oil would be obvious under the cowl nearby. Even a pinhole sized split in the filter will result in major oil loss pretty quickly.

[Grumpy56]

Thank you for the replies. We will try to look at it tomorrow and get back with what we find. A little more info, the boat was used two days last weekend in the Gulf of Mexico. Since we are offshore, the engine is not shutoff. Engine ran about 6 hours each day and coming in the inlet, it went into limp more, low oil. Understand the comment about oil on the water, just not something we look for.

I will be back, (with findings)
Craig

[Grumpy56]

Disconnected the water hoses from the cooler and connected them together. Started the engine and within 30 seconds oil was dripping from the oil cooler nipple. Clearly the oil cooler is leaking oil, which under normal conditions would be going out the exhaust, so I ordered a new oil cooler this morning.

Craig

[redlowrey]

I hope you didn't run to long in fail safe, the bottom end, mainly the con rod bearings won't last too long without oil pressure.

[rocketrod]

Thanks for the help. I had this issue and resolved it with new oil cooler. Old one was blocked with sand and sea weed after 15 years running in Florida flats. Lost over three quarts over time - overheated on the water. Limped to nearest marina and refilled 3.5 qts oil. That got me home. Future service will include a flush using pump sprayer with salt away directly connected to oil cooler lines-both directions!