coolant drain valve - leaking?

[Phr3d]

This valve on a Yanmar 3gm30f (mine has a hose that goes under the engine) may be doing a slow drip.

Has anyone found this to happen and have a fix?






If I have to order new parts, what is it called or what is the part number? I've been through the spare parts catalogue and am not sure if 18 is the same as the valve on the other side...


am not

 

[Captain Pete]

18 looks to be the drain plug for the block. You want the one on the other side of the engine, which is the heat exchanger drain plug. I don't know the part number but you can see both in the attached. I had the same problem and wound up just tightening things up to stop the leakage. You can see it screws into the heat exhanger and it also has a drain screw so I tightened both.

 

[bsangs]

Just curious why you say it "may be doing a slow drip." Have you actually seen it dripping? (Also, is your coolant level noticeably lower?) As Captain Pete mentioned, you'll want the plug for the other side. Is this the parts catalog you're browsing?
Yanmar Parts List

 

[Phr3d]

Just curious why you say it "may be doing a slow drip." Have you actually seen it dripping? (Also, is your coolant level noticeably lower?) As Captain Pete mentioned, you'll want the plug for the other side. Is this the parts catalog you're browsing?
Yanmar Parts List

The absorbent mat under the engine has been damp, the coolant reservoir is slightly lower each time the engine is ran and the tube has slimy residue. I've been trying to develop something more than a conjecture about the source.

I'm looking at page 36 in the "3gm30f spare parts catalog" which appears to be the same document as in your link.

I had the same problem and wound up just tightening things up to stop the leakage.

Thanks - this makes me think I'm on the right track.

I have tried closing it more and didn't want to break it (if that wasn't the source anyway). I remember seeing the diagram for the fresh water and couldn't make sense out the zig-zag line showing placement then.

It looks like your attachment is from the service manual. Funny how the different documents call them different things (and none use the word valve...).




I think opening and closing repeatedly will be my next strategy to see if there is something blocking the seal inside the thing. Maybe I'll order one as well, just in case (Hmmm, $48.08). The part number appears to have been replaced.

 

[Phr3d]

I made some time to run the boat at the dock and paper towel/flashlight inspect for the leak. Coolant was dripping from the hose above it. The clamps all needed to be tightened on all the hoses. Unfortunately, I had to remove the hose and clean the fitting (and go through the burping process again) to get that hose to seal correctly.

No leak and hot water working now.

 

[Loren Beach]

"Calling Mr Occam, to any white lobby phone!"

 

[Phr3d]

I know right?

I guess it's true - most people do not look up.

 

[Phr3d]

So the thing actually was leaking.

I loosened it all the way and worked it back and forth and then closed it firmly. And then more firmly.

It appears to not be dribbling at all now.

 

[Phr3d]

Just curious why you say it "may be doing a slow drip." Have you actually seen it dripping? (Also, is your coolant level noticeably lower?) As Captain Pete mentioned, you'll want the plug for the other side. Is this the parts catalog you're browsing?
Yanmar Parts List

So yes, coolant lower, but no real evidence of where from (maddening really) and there is not that many places it could leak into the tray under the engine. I was almost convinced to look at the head gasket.

Today, I had a white absorbent cloth under it for the Racor service and came back after going to the hardware store to find a green drip.

 

[Phr3d]

The valve is still allowing a very small quantity of coolant to dribble. I have a white paper towel under it and the towel is stained with a very small amount of coolant every time the engine is ran (I change the paper towel each time)

I had the same problem and wound up just tightening things up to stop the leakage.

Captain Pete, How 'persuasive" did you have to be? I used some small pliers to twist the plastic knob more closed last time. I wonder if it is dirty inside...

Has anyone else changed that valve? Or cleaned that valve? Or had a leaky valve?

 

[Captain Pete]

The valve is still allowing a very small quantity of coolant to dribble. I have a white paper towel under it and the towel is stained with a very small amount of coolant every time the engine is ran (I change the paper towel each time)


Captain Pete, How 'persuasive" did you have to be? I used some small pliers to twist the plastic knob more closed last time. I wonder if it is dirty inside...

Has anyone else changed that valve? Or cleaned that valve? Or had a leaky valve?

Hard to recall and hard to describe, but best way is I went as far as I was comfortable and then I went a bit more. Removal, cleaning, and reinstalling might help.