Loosing Oil

[GrooteElyandt]

I have a 2004 (4stroke) Suzuki 140hp outboard

Background:
850 hrs.
I use 10W-40 motul engine oil, live in the hot tropics
Engine sounds and runs great, not missing, no shaking and getting the power and rpms as per usual operation.
On Island we use an opal petrol. Low on lubrication elements so I add a small amount of 2 stroke oil (200 to 1) ratio in the fuel tanks to help lube the valves etc...
Last general service at 800 hrs.
Anodes changed at 750 hrs, (internal/external) no major corrosion.

Problem:
Last 5 runs been loosing oil while operating.
Went for a run the other day for 6 hours and lost approx 1 litre of oil.

No blue smoke or oil burning smell coming form the engine.
Pulled the cowl and side pannels off, no evidence of an external leak, (would be very evident if 1 litre had leaked out)


When the boat is in neutral an oil sheen is seen around engine.

I suspect the oil is getting into the water cooling system and is leaking out through the exhaust and/or the tell tale.

Advice has come my way that it could be the oil cooling system where the oil filter screws in. If this is corroded or damaged the oil pressure could be leaking back through the weaker water pressure hoses therefore getting into the main cooling system. Is this a possible cause?

Is there any other possible causes where oil can be leaking into the cooling system? How else could I be loosing oil given these circumstances?

Any help is appreciated

Cheers!

[Moonlighter]

It could be the dreaded corrosion problem found on the earlier model 4 stroke Suzukis in the 90-140 hp series. Basically a steel plug in the block where here shouldnt be one .....

Check on this site for corrosion problems on DF140s and it shows you where the problem is. The good news is if you find it before too much other damage is done it can be welded up. Again, search this site and there is info aout how others have fixed the problem. Although it could be a bit interesting getting quality alloy welding done up where you are in remote places!

Good luck!

ML

[jHydroman]

I would definately check the oil cooler first, it is the assembly that the oil filter screws to.

I would start by removing the water lines from the oil cooler to see if there is any residual oil visable. You can also pressure test the water side of the coller to determine if it holds pressure.

Jim

[Swanie1975]

When I was researching options for the repower of boat I'm pretty sure I came across posts about df140s losing oil and it was coming out the exhaust.
From what I remember it was usually something do do with salt buildup around the oil cooler area and it was even happening on motors that were flushed out after use.

This was from a google search for df140 problems.

Hope this helps

Cheers Ryan

[GrooteElyandt]

Yesterday 11:58 PM
jHydroman I would definately check the oil cooler first, it is the assembly that the oil filter screws to.

I would start by removing the water lines from the oil cooler to see if there is any residual oil visable. You can also pressure test the water side of the coller to determine if it holds pressure.

Jim


Really appreciate the feedback! Planning to disconnect the two water lines that enter the oil cooler and connect them to eachother essentially bypassing the oil cooling system. If oil starts coming out of the oil cooling nips than I know I've got a problem with that unit...

Will this approach work or will the oil be coming out of the oil cooler anyways because I have taken off the counter acting water pressure lines? Those nips should hold back the oil pressure regardless though considering the oil to water pressure ratio would be something like 45 to 2 psi? Just making sure im on the right track here to pressure test the cooling system.

Cheers
Ian

[jHydroman]

You are on the right track, you can run the engine with the water lines removed and connect the ends of the water lines that you removed together.

If the cooler is leaking you should see oil on the ports where you you removed the water lines.

You are correct the oil pressure is much higher than the water presssure, I expext oil pressure 45-60 psi and water pressure 10-15 psi.


Jim