Yanmar 2gm mystery oil leak

[petersea]

CPT Jon,
I think what you are referring to is low or ultra low sulphur diesel. During the years of change over from the high content sulphur fuel there was both available however in the more recent years (last couple anyway) I don't think they make a high sulphur diesel fuel. Most of what you will purchase at marina or fuel station will be the "new" low or ultra low diesel fuel. The red dye is added to show that that fuel was "off road" fuel as opposed to "highway" fuel. It is basically a tax issue so that trucks pay highway tax on the fuel they purchase.

 

[Cpt. Jon]

CPT Jon,
The red dye is added to show that that fuel was "off road" fuel as opposed to "highway" fuel. It is basically a tax issue so that trucks pay highway tax on the fuel they purchase.

That much I know is absolutely true. I have heard rumors of the police actually checking suspected abusers...

 

[CaptKen62]

I had the same thing happen to me.

I assumed that the red oily substance in the engine bilge, which I just noticed for the first time this weekend, was transmission fluid. Reading above posts, I'm now hoping (praying) that it is diesel fuel instead. The oil level in the transmission does seem low, and as a consequence, I can't tell much about the characteristics of the fluid therein. Since I don't know how long it has been since the transmission fluid was changed, I will change it. I drive an '86 Hunter 31 with Yanmar 2GM20F, and it seems the consensus is to use a 30 Wht. motor oil rather than ATF. I saw no leaks on visual inspection of the transmission, but it is admittedly difficult to see the underside of it.

Does anyone have a rough idea of the capacity of such a transmission? I have heard that it holds only a fraction of a quart. In case I am wrong, and there is a leaking seal or worse, how difficult is it to access and change the seals on such a transmission? Does the engine need to be removed to do so? Are parts even available, and if so, where? Entire new or reclaimed transmissions?

Any thoughts would be much appreciated.

 

[Steve Dion]

Ken:

The trans capacity is about .25 liter or 8 oz. as I remember. You may want to sort of flush it out with clean oil if it has had ATF in it. If the color has turned to a medium brown it is just old 30wt oil (manual recommended fluid).

I doubt that it has done any damage, but I would not be suprised if it may cause the trans. to leak.

When you check it you should NOT screw the cap on, but just set it on top of filler hole with dip-stick in the oil. If it is over filled be sure to lower the level.

 

[Steve Dion]

That is a good point about the color of the diesel fuel. Not all diesel will be red. Only non-road fuel is red. If the tax has been paid it can be used "on" or "off" road, but you cannot use red diesel on the highways.

 

[CaptKen62]

Steve,

Thanks for the info.

Ken Henson
1986 Hunter 31 "Freedom"

 

[Steve Dion]

Ken:

Here is a great reference for many questions that you may have.

http://www.yanmarhelp.com/index.htm

Regards,

 

[Deleted member 78819]

I can't remember the exact reason, something to do with an additive that they don't add or something that they remove from the diesel sold for road use. I think it's sulfur, and I think that diesel engines like sulfur and I think the they do not add or perhaps they remove the sulfur from the on-road diesel. I believe that if you use on-road diesel that you are supposed to add an additive to it.

I just a computer geek sailor, so I could be wrong, this is just my understanding.

The red/off road diesel sold by our marina has a biocide in it. Not sure the over the road diesel does...

 

[Steve Dion]

I doubt that the stuff that truckers would purchase would have this in it. It is only in the tank for a day or so and then another fill up.

I do not think that most marinas would spend the extra money on such a product either. Consider yourself lucky, the marina is looking out for either you or themselves. Hopefully they also change their filters quite often.

I know the Costco stations in our area time how long it takes for their pumps to pump "x" gallons of fuel. When the pumps slow down, they change the filters on the gasoline pumps.

 

[Dan Johnson]

Don...

I think Captn. Jon is on the right track. I believe it's because off-road diesel (red dye) doesn't need to meet the Ultra Low Sulfur Content specifications that highway (clear) diesel does. It's effect is on the valve stems if I'm not mistaken. Rich H may chime in here as he's the resident petro expert.

 

[CaptKen62]

Further investigation revealed that the transmission contains clean motor oil, nothing red in there. I checked and tightened all of the fuel system fittings in proximity of the engine. I am certain now that the red stuff in the engine bilge was diesel fuel. What a relief that I don't seem to have a leak from the transmission!

Ken Henson
'86 Hunter 31 "Freedom"

 

[Steve Dion]

Ken:

I suggest that you order a handful of banjo washers and a few nylon ones. Wipe down you engine and see if you can determine where it is leaking from. It may follow a hose or a wire, so DON'T BE fooled.