Oil in my Bilge

nolasafari · Jan 20, 2014

Clean the engine and the bilge several times. The oil could be residual oil from a previous leak or spill. You could get Oil Trace Dye and add it to the engine, then the transmission, eliminating one or the other. If you can get the bilge dry slide paper towels under the engine and transmission and see if you get markings.

Captn TJ · Jan 20, 2014

sd1953 said:
I bought a 27 year old boat (an Endeavour 38 center cockpit) and I have been resurrecting it over the last year. This is not my first boat, but is my first sailboat. Previously I sailed other people's boats and charter boats. When I bought the boat there was oil in the bilge (a lot of oil). I got it cleaned up and got on with my work. Last week I discovered the bilge with a layer of oil again. I thought to check the sources of oil, the engine crankcase and the fuel. I checked the diesel (Yanmar 4JH3E) dipstick, crankcase is full. I checked the fuel tank, no evidence of leakage there either. I followed the fuel lines, no evidence of leakage there. So there was a layer of oil on the little bit of water in my bilge, but I cannot find the source. If I cannot find the leak, I can't fix it. I'm at a loss. What else should I be checking? Anyone else chased an oil leak around the bilge?

Pretty big difference between oil and diesel in color, odor and viscosity. Not sure why you're tracking the fuel lines if you think it's oil.

Step one clean up the engine completely with no evidence of oil. Clean up the engine pan and place a oil absorbent pad.

Step two: Run the engine and and run to heat up and build pressure. Check the engine completely - up down and around. a leak should be self evident.

capta · Jan 20, 2014

There is sort of microbe that inhabits boat bilges that smells and feels like old oil. After cleaning the bilge, try putting some bleach in there and see what happens. Not to be an alarmist, but rear main seal leaks generally leak into the bell housing and drip from a weep hole under it. Very hard to see as it's generally very close to the hull, or at least the lowest point on most installations.
As above, I always line under the engine and trany with oil absorb pads to see any developing leaks. They get dirty in time so change them to keep a good visual indication of what's happening under the trany and engine.

higgs · Jan 20, 2014

It only takes a few drops to put a sheen on your bilge water. Could it be from your dipstick when you check your oil. I have a similar problem, but have not been able to locate any leak either.

cookwithgas · Jan 20, 2014

sd1953 said:
I bought a 27 year old boat (an Endeavour 38 center cockpit) and I have been resurrecting it over the last year. This is not my first boat, but is my first sailboat. Previously I sailed other people's boats and charter boats. When I bought the boat there was oil in the bilge (a lot of oil). I got it cleaned up and got on with my work. Last week I discovered the bilge with a layer of oil again. I thought to check the sources of oil, the engine crankcase and the fuel. I checked the diesel (Yanmar 4JH3E) dipstick, crankcase is full. I checked the fuel tank, no evidence of leakage there either. I followed the fuel lines, no evidence of leakage there. So there was a layer of oil on the little bit of water in my bilge, but I cannot find the source. If I cannot find the leak, I can't fix it. I'm at a loss. What else should I be checking? Anyone else chased an oil leak around the bilge?

The same thing happened to me right after I brought home my C&C 31. It really alarmed me until I discovered the oil warning sending unit with oil around it. I went to the auto parts store with the bad one and had the guy find one that looked like it and it worked like a charm for only a few bucks. The yanmar dealer would not have let me off so easy. That was a few years ago and I haven't seen a drop of oil in the bilge since. And the oil beeper announces low oil pressure as soon as I kill the engine.

Paul Mermelstein · Jan 20, 2014

You said the boat is 27 years old and you have a Yanmar 4JH3E. That engine is not as old as your boat, so the boat was repowered probably 10 years ago. It is usually a very solid engine. How many hours on it?

jibes138 · Jan 21, 2014

Sometimes when adding new oil during an oil change a person with a shaky hand might spill a little. If not completely wiped up this could find its' way to the bilge. You should pull up the floorboards and try to trace the flow of the oil to its' source. Also put a few oil absorbent pads in the areas leading to the bilge, pumping contaminated bilge water overboard is a big possible fine.

GMatthesen · Jan 21, 2014

Oil in bilge

A very amature mistake is that the oil filter may not have been screwed in tightly. Also different brands have different amounts of gasket face, and may leak if not well hand tightened. I had a great deal of black oil in the bilge, after an oil change, so I can say even experienced weekend mechanics can make amature mistakes.
Good luck
Gary

jibes138 · Jan 21, 2014

sd1953 said:
jibes138 and GMatthesen - I haven't run the engine enough hours to need an oil change (fluids were new when I purchased the boat). But it is sound advise for my oil change procedures.
.

I wasn't suggesting you had changed the oil. What I was suggesting was the prior owner may have spilled some while changing it in the past and it is seeping down a path to your bilge. On my engine the oil fill is near the rear of the engine and there isn't much clearance overhead for funnels and oil bottles. I have to be very careful not to spill some. I usually use a plastic cup and fill it repeatedly to get 4 quarts in there. Even if you find a leak and stop it you will still have oil from the leak all the way to the bilge, you need to clean that whole path to make sure you don't contaminate the bilge any further. Usually this means pulling up the floor boards and using rags and absorbant mats to mop up any oil and oily water you find. Also put a few oil absorbant pigs in your bilge to absorb any oil that gets in there.

Chris Patterson · Jan 22, 2014

Bear in mind a teaspoon of oil/fuel in the water looks like a five gallon spill from above.

(That was also what I used to tell bikers that fell in the road. A teaspoon of blood looks like a quart on the pavement).

It does..

sailorhokie · Jan 22, 2014

If you've bee out sailing its possible that the oil came out of the dipstick tube while heeled, especially if the dipstick doesn't seal well.

Also, if you've motorsailed the heeling (esp. If excessive) and running engine may have forced oil out of the dipstick tube

Josh

redhead78 · Jan 23, 2014

Before my repower my renault ws blowing oil all over, final killer was head gasket. I would have clean water in the blige, alittle dirty oil, and diesel it looked like the Valdez when I was running it. It was a dirty black pool....but if you used a hand pump and placed carefully at the deepest point the water is heavier and would come out just a little colored, the very top was oil and diesel....yick.. Red