I proud new owner of a Hunter Vision 36 built in 1994 with a Yanmar diesel with 2000 hours on it. I have a question for more experienced boaters. There is a very constant small oil sheen that comes out of the exhaust. Is this normal?
Oil sheen
- Thread starter mcelduce
- Start date
Your engine cooling water really gets around. There are a number of possible causes, including a small likelihood that it is coming from your bilge pump and not your exhaust, or that there is a sheen in your marina (this is unfortunately true in many places). If you can eliminate these, here are some thoughts:
Cooling water pump - if recently commisioned, it could grease or soap that was used to lubricate your impeller, or (hopefully not) be oil bypassing the oring. I don't know your engine. I monitor my oil level very closely by checking it before start, cold iron. My idea is that it should not go up (intrusion of fluid) or down (leaks, etc).
Heat exchanger - cooling water flows over engine coolant in what should be separate circuits. If there is coolant in the sea water side of your exchanger you need to replace that part. Or if your coolant expansion tank is "low", something is going on there?
Cooling water pump - if recently commisioned, it could grease or soap that was used to lubricate your impeller, or (hopefully not) be oil bypassing the oring. I don't know your engine. I monitor my oil level very closely by checking it before start, cold iron. My idea is that it should not go up (intrusion of fluid) or down (leaks, etc).
Heat exchanger - cooling water flows over engine coolant in what should be separate circuits. If there is coolant in the sea water side of your exchanger you need to replace that part. Or if your coolant expansion tank is "low", something is going on there?
Of course it is.
Why? Because exhaust gases are mixed with the cooling water before it gets to the muffler and is pumped overboard.
Not an issue.
No, one should not see a noticeable oil sheen coming from the exhaust.
We can presume your engine is a Yanmar 3GM30F engine and that the oil output has always been a constant. Please let us know:
1. What grade oil are you now using ?
2. Where is the level on the dipstick ?
3. Do you notice any significant oil loss between oil changes ?
4. Does the engine show grey smoke over 3,000 RPM ?
5. Does the engine start easily or or not when cold ?
We can presume your engine is a Yanmar 3GM30F engine and that the oil output has always been a constant. Please let us know:
1. What grade oil are you now using ?
2. Where is the level on the dipstick ?
3. Do you notice any significant oil loss between oil changes ?
4. Does the engine show grey smoke over 3,000 RPM ?
5. Does the engine start easily or or not when cold ?
Ralph, I think the issue could well be the difference between these two quotes.
Small vs. noticeable.
Without any photos or more info, hard to say.
My point wqas simple: exhaust gases have some oil in them. Ever drain your muffler?
Your questions remain valid.
Point well taken, however philosophically speaking, he did say he was able to see the sheen and if he can see it, it's too much. Of course my Yanmar uses oil (about 1/8" per year) but it's too small to see at the dock. And to round out this little pontification, I suggest he would be blowing the least amount of oil at the dock compared to fully loading the engine away from the dock where it would be much greater.
The engine I have is 3JH2E Yanmar engine with 2498.3 hours on the engine. I have not noticed any oil being burnt. At 2484.6 I did change the impeller and I used petroleum jelly to lube it. Should there not be a little bit of a Sheen if the cooling water and Diesel fumes mix. I would assume most diesel engines do not get 100% burn. Is this correct?
Excess diesel oil, as in a rich burn during combustion, should result in black smoke.
Burnt lubrication oil should result in blue smoke.
Regardless, as you say, the presence of a sheen in the exhaust water should mean a sheen in the muffler, since that is the last place it goes before leaving the boat.
OP. Have you emptied your muffler into a clear bottle and allowed the fluid to settle? The resulting stratification, if any, will tell you a lot. You could do the same thing with the sw side of your ht ex I guess, if your muffler location prohibits this.
Yes. you are correct.
The Cole's Note's version of fossil fuel combustion runs as follows:
1. In perfect combustion, carbon produces carbon dioxide (CO2) and hydrogen produces water vapour (H2O). This should be the majority of the exhaust gasses.
2. In less efficient combustion, carbon produces carbon monoxide (CO). There is always some of this in the exhaust.
3. In even lesser efficient combustion, carbon produces particles of black soot (C) (elemental carbon or black smoke). There is even a smaller amount of this in the exhaust.
4. Even worse than that, carbon may remain as a hydrocarbon and produce a gum which, if hot enough, could produce an oily sheen.
Hopefully, the only things in the exhaust are CO2, CO, and soot.