Antifreeze

[Weasel]

My friends boat is a 2009 Beneteau 30. It has an approx. 5 gallon hot water tank that is heated by 120vac shore power and the anti freeze line off the heat xchanger. We can run the boat under load at the dock for hours and have no coolant leak. We go out sailing and the bilge is full of antifreeze. Seems like the stuff is coming from under the pan, thru the limber holes. I traced the line back to the engine checking all the clamps for security. All tight. The over flow container is secure so that’s not causing it. I’m not sure the previous owner even used the hot water system. I’m baffled. Anybody have any suggestion. This is driving us both crazy. Water heater is under the port side settee.

 

[Don S/V ILLusion]

Pressure test the system.

 

[Davidasailor26]

Has this happened more than once or twice? The pan holds a remarkable amount of liquid in hidden spots that eventually comes out when the boat heels. If this keeps recurring you might have some kind of coolant leak, but if it’s just been once or twice I wouldn’t assume there’s a problem yet.

 

[Tally Ho]

Seems odd that you can’t make it leak at the dock…is the engine getting up to temp while “under load for hours”?

If so, then I am with @Davidasailor26…could be AF trapped under the pan that ends up under the engine when the boat is heeled over.

How much are you losing from the HX when you sail? Can you that the level is down in the HX? Or is the evidence the AF in the bilge?

You mentioned the water heater…do you suspect that is the source of the leak?

Greg

 

[Ralph Johnstone]

The over flow container is secure so that’s not causing it.

Has the level in the overflow container dropped OR put another way, have you added any AF since this problem in the bilge appeared ?

 

[dmax]

Pressure test as Don says or wrap paper towels around places it could leak and run it - it will be obvious. Make sure to check the pressure cap.

 

[Weasel]

I'm going to try and answer each question.
* I thought the pan might be full of antifreeze from a previous situation, but the quantity of the antifreeze in the overflow tank flow shows a loss of coolant.
* My friend tells me this happens every time he goes out. Especially when sailing.
* Overflow container was checked and it is secure.
* I think we can rule out the water heater, as there is no residue at the hoses or on the shelf were located.
? What could be wrong with the pressure cap?
? How do you do a pressure test, what do you need, and how is it connected?
** Thanks guys! I knew I could depend on y'all to come up with some great ideas and suggestions.
I will await information for pressure testing.

Weasel

 

[Claude L.-Auger]

Pressure caps can get bad and lose their sealing capacity ! But running the engine under load should let you see a leak at the cap if it is bad. Next, get a short piece of hose and disconnect the in & out hoses from the HX to the tank. Install the short piece in lieu of the hoses going to the tank. That will bypass the tank. Go to a tool rental place and rent a pressure tester, or borrow one from a car mechanic ! Easy to use. You just remove the cap from the HX, & fill the reservoir to capacity. Instead of the cap, install the pressure tester and pump it. The system should show anywhere from 13 to 15 psi. Should remain stable. If it gets lower over time, then you have a leak somewhere. You can also run the engine afterwards and check but if you do have a leak, it will show with the pressure tester. Once you have made sure there is no leak on the engine, remove the small temporary hose and reconnect the hoses to the hot water tank. Refill then take another pressure test and check that it remains stable. I had the same problem and the issue was one of the hoses going from the HX to the tank had chafed and was leaking directly into the bilge. I replaced both hoses and problem was solved . Good luck

 

[Don S/V ILLusion]

? How do you do a pressure test, what do you need, and how is it connected?


Weasel

Rather than try describing here, Google is your friend - do a search for testing cooling system (not the A/C system). Lots of links and videos.

While you can buy a nice $200+ pressure tester, for a one -off test you can buy a simple manual pump/pressure gauge instrument for cheap and connect it to the ‘radiator’ cap on the engine. Saves a lot of guessing. The gauge will indicate if there is a leak. All you need to do is find where.

 

[JoeWhite]

Cheapest way is to install a new cap.

 

[Ralph Johnstone]

* I thought the pan might be full of antifreeze from a previous situation, but the quantity of the antifreeze in the overflow tank flow shows a loss of coolant.

* Overflow container was checked and it is secure.

These two statements say that the pressure relief cap is not leaking or discharging as the relief cap leads back to the overflow container through the discharge hose when it releases.

This would keep the tank at a constant level.

Unfortunately, I don't think there's a cigar waiting for you there.