What Color Should Oil Be On Dipstick for 40 HP YANMAR - 3JH5E - SD 50?

[blue-moon]

I have 40 HP YANMAR - 3JH5E - SD 50 on my sailboat. The color of the oil on dipstick looks very dark (see picture)
What Color Should Oil Be On Dipstick?

[Wolfe10]

Yup, doesn't take many running hours for diesel oil to become dark. Perfectly normal.


Do watch for any other color or change in viscosity (which could be due to raw water, coolant or diesel getting into the crankcase).

[cofc]

Unless you just changed the oil 5 minutes ago, it's going to be very dark. Like 5,000 mile oil change on your Toyota dark.

[Engine man]

One function of lube oil is to remove contaminants from your engine, [carbon, and other byproducts of combustion] and hold them in suspension, so they are removed during an oil change. Lube oil has detergent in it, to flush and clean everything it touches. Clean lube oil indicates that the oil is not flushing contaminants from your engine.

Your oil is performing it's intended function. Joe

Originally Posted by blue-moon

I have 40 HP YANMAR - 3JH5E - SD 50 on my sailboat. The color of the oil on dipstick looks very dark (see picture)
What Color Should Oil Be On Dipstick?

[Kd9truck]

I have a 4jh5e with 4 k nm on it, the manual says every 200 hrs or 1 year, I change every 100ish and my oil on removal is dark yet translucent and viscus, I can not tell from the photo, I would have a note of concern if the oil on that stick in your picture if it were black opaque and thin in viscosity.

[Dooglas]

Is this your first diesel boat? Diesel leaves some soot behind as it burns. The engine oil quickly acquires an inky appearance.

[JohnHolland]

My last boat with MD7A Volvo the oil stayed fairly clear between 100 hour oil changes and.ran.fine. Does clean oil indicate an internal problem?

[garyfdl]

Black, unless you just changed your oil.

Oil color on the dipstick in the picture is normal.

Now a question for the OP. When was the oil last changed?

[guyrj33]

BLACK

[JimsCAL]

Big difference depending on how complete you are able to remove the old oil during an oil change. In most marine diesels you are removing it via the dipstick tube which usually leaves a small amount of old dirty oil in the crankcase. Put in new oil and run the engine for even a few minutes and the oil is black.

[PineyWoodsPete]

Originally Posted by cofc

Unless you just changed the oil 5 minutes ago, it's going to be very dark. Like 5,000 mile oil change on your Toyota dark.

Yep, even @ 230hrs when I got my boat w/ VW 165HP TDi, black right after a 6L oil & filter change and run for a couple of minutes.


Toyotas though?! My '06 Highlander Hybrid V6 w/ 130,000 miles - as clean as baby oil at change, never burns a drop. The '16 Camry Hybrid, at 40,000 mi has burned maybe 1/4L at change time, and takes on a slight honey color.

[LittleWing77]

Originally Posted by Kd9truck

I have a 4jh5e with 4 k nm on it, the manual says every 200 hrs or 1 year; I change every 100ish and my oil on removal is dark yet translucent and viscus, I can not tell from the photo, I would have a note of concern if the oil on that stick in your picture if it were black opaque and thin in viscosity.

This is a wild spec, isn't it? Especially for recreational boaters, who would find it hard to reach 50 hours a season when mostly using the engine for going in to and out of their home harbour(s).

The crucial part is at least once, if not twice, annually - and if you haul in the Fall, as part of winterization, do a complete oil + filter change before she sits for 6 months on the hard, so all the crap sususpended in the oil is not sitting in the engine while the boat is laid up.

LW77

[Gary Matthesen]

Just as second vote on oil left in the crankcase after draining from the dipstick, often the engine is tipped down in the stern end to match into the drive shaft. There may be as much as a pint of "old" oil left behind. Starting after your oil change will almost immediately turn things black.

[sailorboy1]

Originally Posted by blue-moon

I have 40 HP YANMAR - 3JH5E - SD 50 on my sailboat. The color of the oil on dipstick looks very dark (see picture)
What Color Should Oil Be On Dipstick?

what color was it after you changed it last (after running and rechecking the level)

yours looks "normal" mostly to me

[Nord Sal]

When my Westerbeke had a leaking seal on the drive shaft of its fuel injection pump, the engine oil would blacken within an hour or so from the diesel washing the timing gears.

After I had the pump serviced, the oil would blacken much more slowly and still have some translucence after 50-60 hours. It wasn't much but it was clearly discernable from the prior state.