losing engine oil - VP D2-75

[YKE]

Hi All, happy new year.

want to benefit from the collective wisdom of CF members.

My engine, VP D2-75, has been leaking and losing oil since I bought boat in 2019.

Yes, Silly me I did not get a separate engine survey done.. thought it would be coved by surveyor I employed fm UK at great expense, boat was in Italy.

So, Last euro winter the engine came out and serviced externally, changing all seals, incl water pump, exhaust elbow, reconditioning of turbo, etc. We did not open and touched the pistons, etc. 6k euro latter it was put back early in the season and we had full euro season with it.

But it’s still losing oil, we topped it up at least twice with around 2 lt in 150 hrs for the full season. No leak in the engine room and no black smoke in the exhaust, etc.

Local technicians are struggling to understand the reason, as compression test was good at 19, oil test also was ok, but given we toped it up with new oil it was not 100 % conclusive.

Where is the bloody oil going ?

Any ideas, experiences and recommendations to find the reason for oil loss??

Appreciate your advise and thoughts.

rgds, yke

[Wotname]

If the oil isn't visibly leaking externally, then it must be going out the exhaust (in the exhaust gas or raw water) or into the coolant. It is highly unlikely to be in the coolant or exhaust water as you would soon notice either of these loss paths. Therefore most likely to going out in the exhaust gas - in other words, getting burnt.

Burning oil usually gives blue smoke in the exhaust, not black. Black is usually running rich (i.e. overfilled). Perhaps it is light blue enough not to notice.

You say "compression test was good at 19", what does the '19' refer to?
If it means 1.9MPa, that is awfully low IMO. The service book number is 2.95MPa (428psi) at 240 rpm.

I'm not familiar with the VP D2-75 but I would look deeper into the compression test numbers because right now it seems the oil is getting past the rings and the reported compression numbers are too low.

BTW, is this the turbo model and does it start promptly when cold?

See http://www.darthaven.co.uk/userfiles...ta%20D2-75.pdf

[Lepke]

If the engine is burning oil, there should be a oil sheen on the water. If you have an oil cooler, you could have a leak in the heat exchanger, but you'd also have a oil sheen. Although 2 liters in 150 hours isn't much of a leak and may only leak when the oil is hot. A pin hole leak in the oil cooler, when the oil is cold, often doesn't leak until the oil is thinned.

If 19 means 1.9 mpa, and I did the math right, it's ok.
I'd pressure test the oil cooler.

[Wotname]

Originally Posted by Lepke

........
If 19 means 1.9 mpa, and I did the math right, it's ok.
I'd pressure test the oil cooler.

I dunno what maths you did but 1.9 map (or 19 bar) is 276 psi. The D2-75 has a compression ratio of 23.3. The manufacturer's compression spec for the engine is 428 psi.

So this indicates a decline of 152 psi or 35%.

Now I accept you know a LOT more about diesel engines than me but that seems way too much considering the reported fault of oil consumption.

But yes, pressure testing the oil cooler is sound idea.

[more]

Originally Posted by YKE

So, Last euro winter the engine came out and serviced externally, changing all seals, incl water pump, exhaust elbow, reconditioning of turbo, etc. We did not open and touched the pistons, etc. 6k euro latter it was put back early in the season and we had full euro season with it.


Where is the bloody oil going ?

Any ideas, experiences and recommendations to find the reason for oil loss??

first all data please
year of production yours perkins 404d-22T (engine block 3000€)
total number hours working
usually rpm you and other sail.
do you usually sail over 2300 rpm or under

this engine don't touch fuel injector,engine block,piston,valve
and you are from UK(i think) be in contact with this guy

Volvo Penta NEW D2-75 72hp Marine Diesel Engine & 150S Saildrive Package new 10251 pound
Dorset, South West England, UNITED KINGDOM
https://marineenterprises.co.uk

always you can sell your engine and buy new maybe for 6000€ difference (hahaha)

[Chayal]

OP I’m curious how the compression test was done on your engine. Was the engine warmed up?

19 bar is low compression. 25 bar Is minimum.

[Searles]

If this engine has valve guide seals that’s the first place I would check ,plus check for blow by on the piston rings,all these checks are easy enough to do .⛵️⚓️

[Hyrdflyr]

I've worked on boat engines most of my life and consider 2 liters of oil burn to not be excessive. Look in the cylinders if you want and check the cross hatch in the cylinder walls. Could be the honing wasn't sufficient. I wouldn't worry about it. I
I once motored a boat from Seward Alaska to Bellingham Washington that burned a quart of 40 weight oil every three hours. Cheers. John

[Compass790]

Personally I would ignore 2lt consumption in 150hrs if its not smoking or putting oil in the bilge. You can buy a lotta oil for 6k Euro. I dont know whats normal for that engine. However if you are used to Japanese engines I can see why you would find it annoying.
Doubt if a surveyor would have picked up the problem with no smoke & no leaks.

[DougR]

Unlikely to be going out the oil cooler, as the oil cooler is on the fresh water side. The oil would have to show up in the coolant.

My guess would be the turbo seals......you said the turbo was “reconditioned”....what does that mean?

If you constantly run the engine at low revs, before the turbo develops any boost, you will have vacuum in the inlet tract instead of boost pressure, and that can pull oil past the turbo seals. Suggest you check beneath the aftercooler drain hole and see if you have oil drip on the flywheel housing. (You will always have some drainage here, just a question of how much)

As some have stated, one liter in 75 hours isn’t too bad....depends on total hours.

[Chayal]

1L/75h I’d run it too without hesitation.

[Pillard]

Was a culprit ever positively identified?