Sporadic coolant loss

[jhwelch]

Ever since entering the warm waters south of Cape Cod on my trip south I've been closing off the bypass valve completely to run at my normal temperature of 160+.

This is a FWC engine. Some nights after stopping I have forgotten to open up the bypass value and in the morning have started up the motor and headed off.

Four times after doing this (usually I do remember to open the bypass valve at night) I have noticed a low condition on my overflow bottle. It takes 3 coffee mugs worth of liquid to bring the level back to normal.

I am wondering if having the bypass valve closed when the engine starts in the morning may have caused extra pressure and thus a seepage out the water pump seal? There's no other place for water to escape from. I do find some wetness below the pump but cannot say conclusively that it is from a drip.

Even with the bypass closed the temperature seems to have been a little warmer than previously. I wonder if the inside of the pump has also become worn. Does anyone have the specs for the inside diameter? It may make more sense to get a new pump than to rebuild the old one, which has about 2,100 hours on it.

-Jonathan

[Dave Neptune]

Jonathan, unless the inside of the pump is really chewed up they're for the most part easily rebuildable. On the inside the part that wears the most is the shoe which controls the displacement of the pump. The shoe is usually held on with a single screw from the outside. For most pumps there are a few shoes available depending on the volume needed. The res is just a bearing or possibly 2 and a couple of seals. Not a bad job at all. If you have it off checking the widths of the impellar is easier to make sure you get the correct "kit".
Or it may just be time for a flushing .

Dave Neptune

[msauntry]

See any coolant in the bilge?

[jhwelch]

I don't see any coolant in the bilge because
1) It is 5 feet deep (my modified full keel is partially hollow all the way to the bottom) and always has water in it and

2) my rudder stuffing box has a steady trickle and I have to run my bilge pump for a couple of minutes a day to deal with that issue. (Now that I am no longer underway I hope to pick up some packing and try to add it while in the water).

[sastanley]

jonathon, I think we need to figure out a way to 'capture' the coolant loss so we can determine the source.

What about some of those absorbent oil rags placed strategically around the engine to help pinpoint? They need to be set up so they do not absorb the sea water from the rudder obviously to try to narrow it down.

The other possibility is a failing waterjacket and you are seeping antifreeze into the combustion chamber somehow.. You should be able to smell that out of the exhaust though. Does it happen only when you close the bypass? ?

edit - I have found that my hose clamps at various fittings leak much more frequently than things like pump seals (although I had to rebuild my 1977 Oberdorfer pump the first year I had the boat because sea water was leaking out of the seal.. ) A dry rag wrapped around each fitting should show green antifreeze quite clearly.

[ndutton]

Could you fashion a separate catchment under the engine? I had one on my Westsail (same deep bilge) and I've seen crane trucks with essentially a giant diaper under the hydraulics to catch the drippings.

[Dave Neptune]

At work and on many things when looking for a leak I simply clean up underneath and then look for the wet spot, not always easy on a boat. A clean piece of cardboard suspended under will show where the leaks are landing and you can chase from there.
Another trick is using a mirror where you can't see and looking for the clean spot on the engine or even a clean streak. The clean is usually the path and there is usually a teltale build up of grime along the edges sort of like a mini river bank.

Dave Neptune

[sastanley]

Dave, I have so many 'river bank' grime trails in my boat, they might as well be Niagara Falls..

[JOHN COOKSON]

Originally Posted by sastanley

I have found that my hose clamps at various fittings leak much more frequently than things like pump seals (although I had to rebuild my 1977 Oberdorfer pump the first year I had the boat because sea water was leaking out of the seal.. )

I've been using TFP paste on my water related barbs on the boat for the past few years. It helps with the seal and makes the hose easier to remove when the time comes. I find that I don't have to use as much hose destroying clamp pressure with the TFP seal. Double clamps also help whenever it is possible to use them.
Also I've been using TFP paste on my water pump gasket with good results.

TRUE GRIT

[jhwelch]

In a burst of energy yesterday morning before the heat and humidity here in Florida got to be too much I took off the water pump. Below it was a rusty area. Ken told me I had ordered a rebuild kit for this pump 2 years ago so I have had more than one instance of dripping.

Another rebuild kit is on the way. Since this issue is very intermittent I will do the rebuild and hope it solves the problem (at least for another 2 years!).

With the block drained and much easier access to that side of the engine I also took off the heater hose from the pump to the sideplate. The dipstick had been rubbing against it, partially cutting into it, before I saw what was happening and took steps to prevent additional chafe.

-Jonathan

[sailbristol]

Originally Posted by jhwelch

I don't see any coolant in the bilge because
1) It is 5 feet deep (my modified full keel is partially hollow all the way to the bottom) and always has water in it and

2) my rudder stuffing box has a steady trickle and I have to run my bilge pump for a couple of minutes a day to deal with that issue. (Now that I am no longer underway I hope to pick up some packing and try to add it while in the water).

I pulled mine while in the water, had the rings of flax pre cut so it took no more than 15 min to replace only shipped about a gallon or two of water but its nice to have no more pesky leak

[jhwelch]

My pump rebuild kit arrived on Monday night and yesterday I rebuilt my pump.

Here are some photos of the old parts. Apparently both seals had failed somewhat. When I did oil changes the amount removed did not see less than normal, nor did it look milky.

The back plate has some minor scoring so I think it is still usable.