Diesel in the sump?

[PedroPV]

My volvo penta 2003 never needs oil. To the contrary, it looks like creating oil in the sump, as its level goes higher and higher. The inline fuel pump is not leaking to the sump. Could it be the high pressure injector pumps? How is that possible?

[Celestialsailor]

Have you checked your coolant level lately?

[PedroPV]

Celestialsailor: The motor is cooled by the sea water and so it has no coolant level. It works well and the motor working temperature is the correct 60º C, even at high RPM.

[Celestialsailor]

Then the possibility is seawater is going into the oil. Maybe through the head gasket or other means. Engines do not make more oil. I had a 2003 and it was also seawater cooled. Not the most bullet-proof engine I ever owned.

[markcouz]

Disclaimer: I am no mechanic!

I had a diesel vehicle (Mitsubishi Triton) which for some reason (after injector service so mechanic reluctant to explain it) allowed diesel fuel from above the piston to blow past the piston rings into the crank case, causing oil level to rise.

This went unnoticed until the excessive oil level in the crank case resulted in the reverse happening- diesel/oil from the crank case blew past the rings resulting in runaway engine, excessive rpm, some engine damage.

If your oil level is rising then find the cause fast. I was able to stall the engine by putting in 5th gear and applying brakes, not sure how that would work out on a boat!

Note: if it happens you would need to cut intake air which may be difficult to do in a hurry.

[capt jgw]

Diesel is a lousy lubricant, so if it's getting into the crankcase bearing damage is likely to result. If it's water intrusion that will cause corrosion. Either way it's bad.

[chris95040]

Originally Posted by PedroPV

Celestialsailor: The motor is cooled by the sea water and so it has no coolant level. It works well and the motor working temperature is the correct 60º C, even at high RPM.

What does the oil look like? Cloudy/Milky?

[markcouz]

With diesel in my vehicle crank case it was hard to tell visually, no milky look as would be expected with water.

[Reefmagnet]

I had water getting into my engine unknown to me for quite some time. It got in via the raw water pump. It never formed a milky emulsion (although the timing case and oil galleries sludged up). Oddly, the oil never went black but tended to stay honey coloured with a slight haze.


Anyway, the way to test if you've got water in the oil is to heat up a frypan (only if you're better half isn't around!) nice and hot on the stove, then drip a few drops of your engine's oil onto it's surface. If it sizzles - you've got water in the oil.

[Bill O]

Originally Posted by PedroPV

My volvo penta 2003 never needs oil. To the contrary, it looks like creating oil in the sump, as its level goes higher and higher. The inline fuel pump is not leaking to the sump. Could it be the high pressure injector pumps? How is that possible?

Just to be clear, by sump you mean motor oil pan?

If it was excessive water, it will look like a milk shake (thick). If it's fuel it will just look like oil, but thinner.

You'd easily see the water, so let's assume it fuel.

Since you don't have an engine attached fuel pump, we can rule out the leaking lift pump. So as you suspected its probably your injector pump. Most likely worn o rings/seals in the injector pump. Would pull and get rebuilt, which should solve problem.


Edit: could have your oil analyzed if you aren't certain if its fuel being added into your oil.

[Stewie12]

It is probably the seals on the injector pump that are allowing diesel into the sump. The type of seals are critical, so best get them from the manufacturer. Or take the pump to be serviced by a specialist.

[roland stockham]

Check the compression. This usually occurs due to warn or damaged piston rings allowing fuel to leak past them. It could be wear on all cylinders or damage just to one. Symptoms would normally be some loss of power, engine spins fasted on the starter motor but take time to fire, black smoke under max load. If that is the case only option is a full rebuild. If it is just rings that reasonable, if it is pistons, liners and bearings as well may be as cheap to swap the engine.

[Cheechako]

You are getting diesel in the engine oil. Either a spraying injector, a bent pushrod, etc. Some boats will do that with a diaphragm leak in the lift pump. etc.
I had it happen, the engine gained about 1-1.5 quarts of diesel in the fuel in 8 hours of motoring. The push rod had come off the valve rocker and was just laying alongside the rocker! Because the valve wasn't opening at all, fuel was being forced past the rings into the sump.

[Scubaseas]

It's usually a lift pump diaphragm leaking into the sump. Has the original lift pump been removed or all the fuel piping to the lift pump bypassed?

[jmschmidt]

Due regular oil analyses of your engine oil at Blackstone Labs. Less the $30, free sample collection container, free sample mailing in the US. Email message with the completed report and a charge to your credit card will arrive in a very few days.

I have this problem. The oil analysis indicated that my 40W oil cold was only 30W due to dilution with diesel fuel. But when heated to operating temperature the 30W was now only 5W. Big problem. The rest of the report indicted normal or no traces of other contaminates. The compression check showed a bad valve, only 100psi in #4 cyl. No metal in the oil was good news so I'm hoping no ring damage and just unburnt fuel finding its way into the crank case due to the nonfiring cylinder. Otherwise big bucks.