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Aura Columbia 30
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Discussion Starter · #1 ·
I'm a new boat owner and trying to solve this lovely problem my boat has presented me with. It has a Yanmar 2GMF and was winterized 'properly' as best I can tell (someone who knows more than I helped me).

All was fine until a month ago in the dead of Ontario winter I went to check on her as I do routinely. I noticed a fair bit of green liquid mixed with water (from recent rains) in the bilge. In my uneducated opinion it looked like engine coolant. The coolant overflow tank at that time was empty. I checked the engine reservoir (heat exchanger) and there was still a bit in there...

Today I checked again and now there is none in the reservoir, overflow is still empty and there is more (less than before) in the bilge. I'm new, but I'm pretty sure coolant doesn't belong in the bilge!

I cannot find any obvious signs of a leak, the drip cloth I put under the engine is clean. The line between the overflow and reservoir appears to be fine. I can't check the mixture ratio of the coolant to see if it froze as there is none left to check!! but the P/O knew what they were doing so I am 'assuming' it was mixed properly.

WHERE IS THE COOLANT LEAK!!?? Suggestions on what to check?? Have I toasted my engine before I have even had a chance to sail her??

thanks,
Al
 

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old guy :)
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WHERE IS THE COOLANT LEAK!!?? Suggestions on what to check?? Have I toasted my engine before I have even had a chance to sail her??
Al

Very most likely everything is fine. I had the same problem on my former boat with a Yanmar 2GM20F. No problem in the summer, just after the winter when it got really cold where we live in Canada. Take a look at the plastic coolant bottle and see how high it is above the engine in your boat. Here is a link to a picture of my engine in the old boat - see how much above the engine the plastic coolant bottle is! It is over to teh top right. I think it is too high.

I think is siphons out when it gets freezing weather.

And for you eagle eyes out there - yes, I really did have carpet in my engine room. So there!

Rik
 

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Coolant Puzzle

I had exactly the same thing happen to my 1990 Yanmar 3GM30 with about 2000 hrs on it. During the summer the coolant level was at the low end of the mark on the reservoir. But it was not loosing coolant, as far as I could tell and so it was not a problem. Last fall I did the usual engine maintenance; change oil, filters, check belts, impellor, etc. And I completely cleaned the engine bilge. We purchased the boat last summer and this was the first time I had to address the oilly bilge. The boat sat in the water, at our dock in NC, all winter (such as winter is down there, but we did have some freezing temp nights this year). We are not there, but I have a neighbor watching the boat. The bilge has been dry all winter but about a month ago he noticed there was coolant in the engine bilge, but he could not find a cracked hose or any leak. I was down to NC a couple of weeks ago to check on things and I noticed that the bottom of the reservoir plastic container was wet with coolant, yet it was empty!. I opened the fill on the engine and it was full?!? Of course the engine was cold. I thought maybe I had a cracked plastic reservoir, but I could not find any leak. And just like RikHall the reservoir is higher than the engine fill. I added coolant to the reservoir up to the mid point and ran the engine for awhile. All seemed fine, there was no additional leak???

I had to edit this part as I re-read what Rikhall's suggested. He is suggesting the coolant just siphoned out of the reservoir, not out of the engine. I would agree as my engine was still full, the reservoir was empty and the amount in the bilge was about as much as was in the reservoir (nearly empty) to begin with (but I did not measure it). I am rusty on my PV=NRT and I don't have an explanation on how the coolant would syphon and overflow? I had suspected that the cold opened up the seam in the plastic bottle and it just leaked out the bottom, but I could not find anything wrong with the reservoir bottle.

I left this as a mystery to be solved when I was down there and probably after I got some sailiing time in (priorities). :(

Any other inputs to this puzzle are welcome. I also believe your engine is fine.
 

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Coolant in Bilge

Al,
Relevant to this topic but not an answer to our loss of coolant.

http://www.sailnet.com/forums/gear-maintenance/48545-where-put-engine-coolant-expansion-tank.html

The reservoir tank needs to be above or at the level of the heat exchanger on the engine.

The other possibility is that there is a leak at the hot water heater (I have one) and the drop in pressure then pulls the remaining fluid out of the reservoir tank, but that does not explain my finding the outside bottom of the reservoir damp with orange coolant. I did notice that there is no clamp on my hose that attachs to the reservoir tank from the engine. Is it possible the drop in temp siphoned the coolant out of the reservoir and the difference in thermal expansion of the plastic tank nipple and the hose created a leak at that junction? :confused:

Another relevant thread;
http://www.sailnet.com/forums/gear-maintenance/32061-odd-coolant-leak-issue.html

This one also suggest the connection at the reservoir tank to the hose as a possible culprit, but no final answer.
 

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Engine filler cap defective or not on tight might leak but the engine should remain full even if the reservoir is empty.
 

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I don't know the technical name - but the coolant goes to a cylindrical unit as part of the cooling process and on most diesels there is a zinc in there. If the zinc was corroded / gone- may explain why it is going to the bilge...?
 

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coolant in Bilge

Jody,
In some Yanmars there are zinc's in the heat exchanger, but my 3GM30F series does not have a zinc. There are drain plugs and it is possible that one of them leaks. But as A's original post, I had a pad under the engine (trying to find the source of the original oil in the bilge) and the pad was still clean. So it is a puzzle were the coolant leaked out of and why was there a slick of coolant on the bottom of the reservoir bottle. It does seem like the coolant siphoned up out of the reservoir and then leaked out the top of it, down the side and eventually to the bilge. But I don't know the mechanism behind that nor the specific exit from the bottle.

But as I mentioned above there is no clamp at the top of the bottle and perhaps that is the culprit. The plastic bottle is shown here with about as much coolant as was in it when I left the boat. When I returned it was empty and about that much was in the bilge.


:confused:
 

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Aura Columbia 30
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Discussion Starter · #9 ·
The syphon saga...

Thanks so much for all the replies. You put a new sailor's mind at ease.

It is a mystery... but I am happy to hear that the consensus is that the engine is not damaged (we hope) and that I will be able to deal with this fairly easily. I am heading back down on Monday with a friend who is engine smart and he concurred with all of your opinions... cold has drawn the coolant out and down the wall (missing the drip pad) and into the bilge. It has had 5 weeks to drip slowly so it makes sense.

Are there 'zincs' in a 2GMF engine?? 13hp.

Regardless, thank you again for the help. I will move the reservoir up a bit higher and the hunt for the leak continues!! I will let you know if I find the smoking gun...

Al. The boat goes in in 4 weeks... can't wait to start.
 

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Aura Columbia 30
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Discussion Starter · #10 ·
And it continues

Here we go again. I cleaned/dried the engine compartment, the bottom of the engine and the bildge - couldn't find any 'obvious' signs of leakage (that's good...). So, I filled the engine (which still had some coolant in it) and then the overflow up to the midway point. As I poured it into the engine, it DIDN'T POUR OUT the bottom of the engine... again good.

I left it for a day and returned, no signs of leak on the drip cloth under the engine or in the bildge and the levels are as I filled them to - still good!! After a day of steady rain I returned to the boat and found both rainwater and coolant (although a small amount of the later) in the bildge!! #@%% it!!

I checked the levels of both the engine AND overflow and both appear to be exactly where I filled them to. So, based on my complete lack of knowledge of engines, I figure either one of three scenarios: 1. the recent bildge coolant is from the winter leak that has rectified itself and the rainfall has just flushed it down the to its final resting place, the bildge, or 2. the engine is STILL leaking but the levels in both the engine and overflow are not moving because the engine has not been turned over and thus has not pulled the new coolant into the engine, so the levels will not change, or finally, 3. there still is a leak in the engine somewhere and as per #2 the new coolant is not pulled into the engine to show a level change and the engine is just still leaking coolant that was in the engine from last year.

Confused you all yet?? I checked the drip cloth under the engine and it was clean. Makes me believe #1 is accurate and this is run off. The boat goes in the water this morning at 8am... its gonna get interesting here soon. I'm concerned that when I turn it over, coolant is going to go everywhere...

I checked my mannual and it does not show any frost plugs on the engine. I checked the bottom of the engine and I can't find anything that matches the descriptions I have heard of a plug so I have to assume there are none.

There is no sign of contamination in the oil but I have not been able to get at the transmission levels to check that yet...

Help!

Al
 

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Al, do you have a hot water heater that is tapped into the engine coolant system? If so, another poster mentioned the possibility that this could be the source of the leak. It bears investigation. I have never been so lucky as to have a leak cure itself.;)
 

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S/V Loon
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I have red dot heaters that are attached to the cooling system in addition to the engine attached hot water heater, so there are lots of hoses and connections associated with this plumbing and any of them can leak. Plus these hoses sometimes lie against the bottom of the boat, and they can derteriorate there, and tend to be ignored.

So you need to see if there is more to your closed cooling system than just the heat exchanger and the water pump. Follow the hoses into the pump and out of the thermostat and see if there is more to your cooling system hiding in other parts of the boat.

In my case I had a leak that dripped when the engine is running were the hose went into the heater because of a size mismatch. (3/4" hose, 5/8" barb.) The slow coolant leak pooled above a fiberglass stringer, and when it rained, water that leaked through loose stanchions filled the pool and pushed the coolant into the bilge.
 

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Could it be your water system leaking and not an engine? It is quite possible that drinking water tank was winterized with safe albeit green colored antifreeze.
 

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It does not sound like there is anything wrong at all. Were you there for the winterising process?

When an engine is winterised, antifreeze is run through the cooling system. The antifreeze is mixed with water - 50/50, 60/40, maybe even 70/30. The antifreeze that a lot of people use for diesels (and never for water systems) is GREEN. When it's mixed with water it is WATERY GREEN.

When the cooling lines are full of antifreeze, the impeller and the thermostat are removed for the winter and their covers are replaced. During this process, some of the WATERY GREEN solution falls into the pan under the engine.

When the engine's cooling system has been filled with antifreeze, a lot of people will the pour the remaining anti-freeze into the bilge, and pour some more into the engine pan.

This could be the watery green mixture used in the engine, or it could be a dilute of pink or orange antifreeze as well. The pink stuff is okay to use in potable water systems, the orange and green stuff (ethylene glycol based) are not.

I think your engine is fine and that your boat was winterised properly. Do the same thing next year.

Either you have to go down to the boat every 24 hours and keep the bilge BONE dry or you have to put a goodly layer of antifreeze into the bilge for the winter.

The one thing that you don't want to do is allow two or three inches of water to lie there and freeze and thaw and freeze and thaw the whole winter long.

It damages the boat.

Good Luck ! :)
 

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Boon, try this. Disconnect the overflow hose from the coolant bottle, and stick it in a jug or something, so any fluid coming out of the overflow hose is contained.

Then take a good plastic bag and BAG THE OVERFLOW BOTTLE from the bottom. Fill the bottle with anything. Go away for a day and see if the fluid is seeping out some invisible pinhole or crack in the bottle.

Sometimes you get lucky and it is that simple--just a failed plastic with a pinhole so small you aren't seeing it.

If that doesn't work, you clean and dry and spread pads--or talc--under the engine, water pump, cooling lines, water heater, anything the coolant travels through. Come back the next day and look for the drips--or for where the talc has been washed away. A black light may help, the coolant may have a UV trace in it, If not, you can easily add one, the engine/auto shops sell it.
 
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