Westerbeke W50 Cooling Problem

[daedaluscan]

I am looking for some ideas. W50/Leyland 1.8D

My engine is dripping coolant from the header tank overflow drain tube pretty much constantly.

Engine temperature is fine (180°), and I am not dropping coolant level.

No oil in coolant, no coolant in oil. Coolant still bright green.

I am thinking heat exchanger ruptured, but it surprises me that the sea water side pressure would be higher than the coolant pressure. I checked the coolant return elbow and it is clear.

Any ideas or suggestions appreciated. Has anyone changed repaired the heat exchanger?

[Chief Engineer]

If you can post a photo of the heat exchanger that might help.

Did this just start happening?

If you top off the coolant it will overflow as it expands. I am sure you already know that.

This is referred to as "making water" a photo of the exchanger would help. Some have internal gaskets or endcaps (rubber) that can be problematic.

[daedaluscan]

[IMG]file:///C:/DOCUME%7E1/CHARLI%7E1/LOCALS%7E1/Temp/moz-screenshot.png[/IMG][IMG]file:///C:/DOCUME%7E1/CHARLI%7E1/LOCALS%7E1/Temp/moz-screenshot-1.png[/IMG]Heres a photo from the manual. The heat exchanger is the cylinder under the exhaust manifold/header tank.

Yes it seems to be a new issue. We motored about 24 hours over the last two days and it probably spat out half a cup over that time. I haven't added any coolant in the last 100 engine hours. Ambient temps may be a bit higher but the engine temp is consistent.

It does have a rubber cup on the aft end but I have never dared investigate, Guess I will have to now.

[Pete the Cat]

When you take the rubber cap off you will not learn much, as you cannot diagnose a leak in your heat exchanger from there. You may find a lot of crud in there from the remnants of your pencil zinc (you are changing those, right?) and maybe some other crud if you are not using some kind of sea strainer, but none of this is likely to make your expansion tank overflow. Be Very careful to align the rib in the center of the rubber cap with the division in the heat exchanger when you replace the cap. The whole apparatus will not work correctly if you do not get this on exactly right.

I would not add any more antifreeze for a period of time and see what happens. My old W50 on my Tartan 37 ran for 3000 hours with the standing water level in the expansion tank about an inch--maybe more lower than the cap of expansion tank. You might have no problem at all other than the temp being a bit warmer. Start with the cheap solutions.

If the expansion tank is filling regularly no matter what the ambient temp, I would say the next step is to remove the heatexhanger and take it to a good radiator shop and have it cleaned and tested. It is no fun removing this, but it is possible. While you are at it check you exhaust elbow. These are two routine maintenance items that, because they are a pain in the butt to do, rarely get done often enough.

Good luck.

[daedaluscan]

Thanks Ray, that is good advice. I do check the elbow regularly, but I have been apprehensive that the rubber will be brittle so have put off having a look! I don't have a strainer either so may add one.
I am on a dock next week in La Paz and will take it off.
I do change the zincs, but they are probably due.
It does seem to run about an inch below the cap, but it is just the dripping that has made me nervous.

[JiffyLube]

I had a problem once like you're having with our Pathfinder diesel engine (VW), and the problem was caused by raw water mixing with the coolant. On each end of our heat exchanger there are these hard rubber boots, and the tube bundle/stack has to be centered exactly in the center of the exchange. The boots have two places where clamps have to be very securely clamped, one clamp at the exchanger housing to keep liquid from leaking out of the system, and one clamp that keeps the raw water from mixing with the coolant inside the exchanger. The clamps that stop the internal mixing of raw water and coolant, loosened just enough to allow the raw water to enter the coolant part of the exchanger. The raw water forced the coolant level to rise, and a raw water/coolant mix began to overflow out of the engine. In our case the fix was to tighten up all the clamps around the boots very tight. You're system will probably be different than ours is, but the problem is the same. Somewhere raw water is entering into the coolant part of the exchanger.